I just remembered, I still have a dead 4TB WD RED drive sitting on my desk (it is from the same series as yours and is a couple of months newer), it failed on me last year.... I should pull it apart too (that is why it is sitting on my desk, I was going to do a video on it one day!), my drive is from 6th March 2018 and it is also an EFRX version.
there are places that do PCB swaps on these for cheap, often the WD PCBs fail when the drive is mechanically fine. FWIW if you wanted to try and recover the data
@@MrMaxeemum The head mirror acted like a ring light. The forehead position is basically parked; in use it was worn over one eye. A bright light source to the side of the patient gave the doctor a better view of the patient's ear, nose and throat. Of course we've had better tools for the job since the 1930s, but head mirrors were so iconic in the days of silent film that they became a costume trope.
He could hear the drive sounds... Actually in the old big (physical size) drives the head activator look like the coil in a huge speaker and was called "voice coil". Working out that area was really dangerous because it could easily cut your fingers if you were in it's way.
The high capacity drives are filled with helium, that is in order to be able to hover the heads closer to the surface of the platters than atmospheric air allows. The breather hole is needed on non-helium drives because the turbulence when the drives spin up, compresses some of the air, which causes lower pressure on top of the platters, causing the heads to hover too close, so when spinning up, they'll suck in air to compensate (over simplification), the helium drives have a slight over pressure to compensate for this. The white pad is a filter, designed to collect contaminations thrown off the platters. however, activated charcoal filters, and desiccant is common to find also. Regarding the screws, this is very common, i think they use custom sized torx, as i have experienced this many times. The trick is to loosen the screws one by one, and re-tighten them before going on to the next, if you loosen all screws at once, the last screw will carry so much load, that it can be hard to remove. The various aluminum parts are nickel plated, that is why they have a texture that could look like cast some places. Actuator arms have been both machined and cast over the years, but cast is more common in older drives. The head parking feature is used on all HDDs today, because of the flatness of the platters and heads, they will actually stick if they ever contact the platters, so the heads can't rest on stationary platters like they did years ago. Another fun fact, to ensure the heads are parked in case of power failure, it actually uses the platter motor as a generator, to generate just enough power to return the actuator home, before it is spun all the way down.
@@Inertia888 Nope, the 4 motor traces probably go straight to the windings with electronics choosing the energy direction. On the head cable, there'll be fat traces to the speaker coil and to the chip power pins, while the thin traces carry data and perhaps control.
My first thought was that it would be for writing initial data. Thanks, James! I like Quantum. Been around for a long time. Pioneers. (I built the iRobot B21R's).
I thought those would be written before assembling the stack, then ignored on the surfaces that don't need it. Or maybe written by the main head in a special firmware mode that starts by finding the extreme head positions, then step the actuator according to a precomputed curve or sensing the last written servo track weakly as it chooses the next track location (such an algorithm would result in slightly different track counts between drives, hidden by firmware from the logical interface view).
12:17 I’m pretty sure that’s just the recirculating air filter. Any little bits flying around will be carried along the outside of the platters and get trapped there
Air filtration. And the bottom access (removed sealed label/tape) is to write/read rom sectors to drive at manufacturing (boot/block, servo information, etc). Many drives have the factory access on the side (sealed label/tape). Been awhile since I took a recovery class under Scott M. of MyHardDriveDied ... look him up...great resource here in the states.
I think your diagnosis that it has crashed is incorrect. The head positioning is done via feedback from the read signals from the heads, either a single servo head or (in this case) embedded servo information on all heads. There has been a failure in the read amplifier and thus the head servo has lost control, and that is what you see and hear. When you view videos from people who know how to recover these, you will see them replace head assemblies and make them work again (at least to read the data).
Agreed. The noise heard was the continuous seeking due to head or board failure, rather than heads coming in contact with the platters. It’s good to know that most likely the data could have been easily recovered with just a board or head swap. Now if this would have been a Seagate drive….
@@ecaparts Could have been the arm the heads are attached to smashing into the center as well. I have seen that happen more than once. Makes a nasty noise.
My guess is that head contact would have a more consistent frequency. Either a steady screech or something synchronous with the platter rotation. The sound you played was more stochastic, consistent with your conclusion and others that it was seeking gone wild.
The heads are created in layers using the same processes used for semiconductor chips. They go through thousands of operations to build a three dimensional structure using exotic materials (platinum, tantalum, gold, copper, diamond-like-carbon, silicon carbide, etc.). They are oriented vertically (standing on edge), so that thousands can fit onto a single wafer. The crazy part is that they have machines with enough precision to mechanically separate them from each other, with the air bearing surface still in tact (it is not simply a smooth surface).
@@artdehls9100 most of the tools combine photolithography with physical vapor deposition, chemical vapor deposition, ion beam deposition, ion beam etch, electro plating, chemical mechanical polishing. It's all built up in layers. It takes many layers to build one physical feature because the processes have limitations with the geometries they can produce, so the material (wafer) goes back and forth from tool to tool. You may build up a layer only so it can be sacrificed later by some other process that can't differentiate what it should remove from what it should keep. The tools themselves vary wildly in appearance. If they use a vacuum they maylook like large stainless cylinders with lots of plumbing on the outside and a robot arm on the inside. I've seen some that look like washing machines. Others look like Rube Goldberg machines.
In my experience, actual physical head crashes are extremely rare in modern hard drives (especially with 3.5" form factor drives) and the failure mode is almost always down to corruption of the embedded servo data, resulting in the drive being unable to track properly, or a problem with the drive electronics - the hub motor / head actuator drive chips often get very hot and are known to fail. The motors themselves very rarely give problems, so if a hard drive won't spin, it's usually going to be an issue on the PCB. Chattering heads (the actuator arm banging back and forth between its travel limits) is often caused by bad servo data, in which case there's not usually much that can be done to correct it. Total failure of the drive to be detected by the operating system is invariably the main onboard microcontroller/DSP chip and intermittent detection failure is usually just bad cables/connectors. The little "bag" which you thought was a dessicant pack is actually a filter designed to trap any particles that get thrown off the surface of the platters - thses things are generally spinning at between 4000 and 8000 rpm and thus any dust and debris that lands on them will be hurled off at high speed due to centrifugal force - as a result, opening the hard drive in a non clean room environment is nowhere near as damaging as popular myth would have us believe - I've done it many times, particularly on certain laptop drives that have a habit of sticking (I'm looking at you, Samsung) without any problems, and many of those drives are still working years later (9 years and counting for one of my own drives). I wouldn't recommend it of course, but if you absolutely have no other options available to get a drive fixed, then it's not something you should be totally paranoid about, as it is entirely possible to get good and reliable results from this procedure. Obviously you should work in as clean an area as possible, using minimal air circulation (turn the desk fan off), keep your fingers and any tools off the platter surface and try to get the job done and the drive closed up again as quickly as possible. (and try not to let your inevitable sweat drip onto the platters - that's never going to end well :) )
Thanks for this info. I’ve long suspected that head crashes are actually spectacularly rare, likely only to happen as a result of severe shock during operation (like in a dropped laptop, especially in the days before the drives had accelerometers that told them to park the heads as soon as a drop was detected). I had to LOL when Dave speculated the pads on the lid were to cushion the platter in case it wobbled... I guess he doesn’t know how insanely small the fly heights on hard drive heads are. (I suspect the pads are to dampen noise and vibration, but this is pure speculation.)
My vague recollection is that it's not necessarily unsalvageable, just difficult- the tracking data just spontaneously becoming unreadable without any signs of damage is unlikely, and the reason it can't find it, is that something up the chain has failed-heads, flex, amps, etc. Not something easy to fix though- would likely need donor parts with the exact same serial number, and even then there can be different versions. So you'd be spending at least as much as you paid for the drive to fix it just on parts. Not a simple swap either, as there's some level of data on those boards that needs preserving, component level repair is the easier option. The data is untouched, but the information is gone- without the way to properly interpret it, it's just noise
My experience matches yours. Additionally, in my experience a head crash (i.e. when the read/write head makes physical contact with the platter(s)) results in a scratching sound, rather than a click. The so-called "click of death" is actually the armature constantly resetting (as seen in the video).
We pull out head crashed 15k 2.5" drives all the time from the datacenter, almost all of them that suddenly died (instead of g-list getting full) are of that kind
Just looked up their Dutch address printed on the case and yep it's one of those tax dodging buildings. You can look the street name up Taurusavenue 5 Hoofddorp. That whole building has thousands of companies registered in The Netherlands so they pay like 0.1% Tax while they virtue signal on Twitter how much they care.
Yes, I figured that's the only way they could do it. But then you have a chicken and egg, so it would require the servo markers already written before first start up. So maybe that's what that bottom slot is for at production?
@@EEVblog Servo tracks were written on a separate machine back when I was working on drives. Self servo writing is something that has been looked into, But I don't know if its currently being done.
Dedicated servo track platter is prehistory ;-) Modern HDDs use embedded servo, i.e. servo data interleaved with the actual data sectors since eons now.
Used to love taking apart hard drives as a kid. It really felt miraculous, even in the 90s, to have such a precisely made machine in your hands. It's actually a little surprising how superficially similar a modern unit looks to one of those old ones, though I'm sure the engineering has only gotten more advanced.
@Stop Banningme Nope.. Humans at all is too expensive and too clumsy.. This is pretty much machine only cleanroom stuff...The benefits of mass production. Also you can look at drives from different manufacturers, and see how incredibly similar they are. screws in the same spots, castings are identical etc...
@@blitzwing1 I think you’re being facetious at the beginning there... and I certainly hope so... because there are _so many_ things wrong with no-holds-barred capitalism, I don’t even know where I’d begin if I thought I had to explain it here. :)
@Stop Banningme No.. you don't need people to run machines... The factory of tomorrow is without humans... Robots who build robots, AI doctors etc... What a wonderful world.
5:00 That red potting compound or whatever is telling "I'm sorry Dave, I'm afraid I can't do that." 5:30 Traces used for the electroplating that were then cut, I assume? 26:40 Gauge platters, I reckon. Perfectly wrung together.
*17:06* _The coil is an _*_orthocyclic_*_ (non-helical) winding, onto a sector-shaped bobbin._ _You can see the uneven step-over zone of the coil, nearest to the heads, where each loop of wire jogs to the next adjacent winding plane._
If your re-assemble the magnets and drop one of the aluminium rings between them, you can see Lenz's law in action as the ring moves much slower than you would expect.
@@DavidLindes , that is one of the great wonders of the modern world that wasn't around when i was a kid. i have a copper water pipe in this very room i'm in as i type this and a stack of super magnets that snugly slide down the pipe. and whenever i come across more magnets of that diameter i add them to the stack and they slide down the pipe even slower.
I'm sure others have pointed out that with modern drives just changing the torque on the screws on the top plate is enough to cause them to fail. Then you get into the helium filled drives...another story all together.
The helium filled drives have a 5 year lifetime, if you have not replaced all drives after 5 years (does not matter if they are powered on or off the helium is still leaking away) enough of the helium will eventually leak out for the vacuum that is left to weld all the heads to the platters. For the hard disk manufactures it is the ultimate in planned obsolescence. It would be a bit like buying an engine with a very miniscule oil leak where you can not replace the oil, once all the lubricating/cooling fluid has leaked away bad stuff happens.
@@addydiesel6627 largest air filled drive is a 10tb Toshiba Drive, they where somehow able to cram 7 platters in the standard 1 inch high casing without needing to use He. The maximum platter count for air filled drives has been 6 for eons, I have a 18gb quantum SCSI drive from 1999 and that has only 6 platters, again in a 1 inch high case.
@@addydiesel6627 For data centres they make total sense, long term data is backed up to tape, and failed drives are hot swapped with new drives minutes after a fault. Helium is less viscous than air and has better cooling properties so the drives can spin faster (quicker access time). And as for SSD's they are worse for long term data storage when compared to helium filled drives "if powered off" ( See "Temperatures and data retention" in www.jedec.org/sites/default/files/Alvin_Cox%20%5BCompatibility%20Mode%5D_0.pdf the data is from Intel), after about a year powered off the data on Consumer grade SSD drives starts to fade away, on Enterprise grade drives data starts to fade away after about 10 weeks powered off! SSD's are not designed to be powered off for long periods of time. Nothing lasts forever though, so it is all about understanding the limitations of each new technology and how that fits into your own personal requirements.
It's actually not just a desiccant packet. That is the micro particle catch. If something were to get into the drive, it would get flung into that catch.
@@paulcohen1555 You do realize there is ventilation hole right? So the desiccant pack would be fully saturated with moisture by a few days to weeks on a product that is supposed to last years therefor rendering it useless?
@@marksnow8838 But there there isn't a fan behind that hole. It's just to equalize small differences in the pressure. And it's doing a good job when the drive is kept at a constant temperature.
@@paulcohen1555 So what's up calling it a "vent hole"? Regardless a hole allows moisture to seep in, so if its a desiccant pack(which its not), then it would be fully saturated with moisture within a short time span. Anyway the hole at the bottom of the drive is mainly for pressure equalization caused by weather changes, altitude changes, temperature changes etc. The filter beside the platter is to catch any remaining particles after assembly or would be generated during the operating lifespan of the drive. The platters still moves air even though its not shaped like a fan. That is why you need multiple filter in a hard disk.
But they'd all be the same note - you'd need different platters from different drives, and even then, they'd probably have a very similar pitch to them. I bet all the platters are nearly identical in every drive.
The small square bag in the corner is a air filter, the shape of the chamber gives you a clue, the air movement from the platters draws a little air through it as the drive spins. The separation plates between the platters are there to reduce the amount of air that moves across the faster moving edges of the platters, to reduce drag. Quite often in smaller drives the platters are made from glass with a coating applied by vacuum deposition.
+1. There might be some desiccant in there, but the spinning platters create airflow across these pads to ensure that any speck of dust is contained. Dust = warranty replacement.
That white "pillow" at 12:18 is not a desiccant it is there to trap microscopic particles, i.e. from the platter coating, which wears off over the years (makes bad sectors and weak/damaged heads). If you had a head crash you would probably see lots of grey platter dust on that white filter (some platters are just glas discs with a special magnetic coating (nickel alloy ?).
ps2, i saw somewhere that the coating may be ruthenium. there are probably other less exotic substances used now. i dont know of any other use for ruthenium.
Just want to say to everyone, that drives today from any manufacturer are pretty damn robust. They are machined to really tight tolerances and some have the ability to park the heads before physical damage can occur by detecting the G forces applied to the drive. So the damage is less likely to be physical scrapes on the platters unless you've really dropped the drive or given it a jolt. Desktop drives are more easily physically damaged from movement but desktops are less likely to be moved. But really, the most likely failure point for any non-physically damaged drive are the pressure pads that let the signals travel between the board and the motor and heads. At least that is what I've found to be the case. The pressure contacts eventually begin to put less and less pressure on the pads over time and they also eventually start to oxidize, both problems create higher resistances in the connections and that eventually causes issues spinning the drive, moving the heads and reading/writing the data. If you are placing a drive in a freezer to get data off and it's working then those pressure contacts are likely the reason why your drive is failing. I've seen the pads for the head connectors oxidize causing read/write issues and I've seen the pressure connection pins for the motor connector loosen enough over time that the platters won't spin up properly or even at all. Physically cleaning oxidation and bending the pins for the motor connector to make more pressure on the pads is usually enough to give a drive some life support but if you want reliability then it might be necessary to replace any aged pogo style connectors that are going to the head assembly. [... _or just replace the pressure connectors with some carefully made direct wired connections and live a happy life with an _*_almost immortal_*_ drive_ ...] And I've never had to, but if you use something like Deoxit then only use it on the board side and not the mechanical side, or at least be careful and don't spray anything at it. Just use a q-tip or cotton swab and don't get anything inside the mechanical part... I've also seen shorted protection diodes on boards but that seems more likely an issue on external drives and less likely on internal drives unless the power supply is going out or you've got some fancy pants removable drive system. And they really need to add some protection diodes on all power rails right over the motor driver and maybe even the DSP chip, too. Faulty power connections occasionally destroy those things.
@@iliandocx8392 That's where you get into semantics of what is mechanical or not (like does it need to have moving parts) If it's most complex device full stop, then yeah it is UNDOUBTEDLY the CPU
Holes near the read amp have small traces going to them - may be for the gold plating process - connecting all the copper together, then punched out after plating
Also could be used for automated testing when the motor is being made to check resistance and inductance and probably ground leakage, gets trimmed off later .
Or fex last step to open some very sensitive stuff up from shorting them to ground due to ESD reasons. there might be a reason it just at the head assembly.
The big bras "test pads" up near the heads are actually pietzo crystals. apply voltage moves the head left and right. its the fine adjustment to the servo.
Dave, maybe consider running different manufacturers or batches of drives in NAS(unless RAID0). I got WD+Seagate combo, probably not matched in performance, but will not fail all at the same time.
@@EEVblog you think? Had 3 out of 4 6Tb WD Purple drives fail within 2 weeks in a couple of DVRs all installed at the same time and sequential serial numbers...
You're right about them being the most mechanically complex device most people own. The tracks in a modern drive are something like 50 nanometers wide, and the fly height is about 5nm (similar scale to modern CPU transistor size). A modern drive has about 400,000 tracks, and the heads can seek to the right track in, usually, less than 10 milliseconds. Truly incredible. No visible damage to your platters, in which case it may have been a bad head or bad head pre-amp. The drive has a service area which contains parts of the firmware that are needed for the drive to work. If the drive can't read that area on startup (bad head, preamp or scratch in the SA) then it will just start clicking (seek re-tries as it tries to find the SA tracks). Could be various other things of course.
sorry for my poor English, the window on the back is actually a hole for "servo writer" to lock and guide the arm to initialize the hard disk like "low level format". You don't see that window on very old hard disks because they use step motors to locate each tracks. but the new hard disks use voice coil to move the arms, the voice coil won't really locate tracks if the disk platters don't have the "servo tracks". therefore the new hard disks need a servo writer to hold the arm through the window you see on the back, and guide the arms for the write heads to write the initial servo tracks just like "low level format".
Dave, you should know that those metal flanges are being connected by a non-reversible tremie pipe to the differential girdle spring on the “up” end of the grammeters. Also, I wonder if you can "lift" finger prints from that glorious 4K video?
Ah yes, I too remember the pain of an out of nowhere pinched finger lol. Also, be careful with laptop hard drives as they often have glass platters, a friend found out in a surprising way when the patter exploded as he was taking it out with a screwdriver and applied a bit too much force.
This where you come to find that a capacitor in the circuit went open and was causing undesired oscillations causing the heads to miss align and not boot!!!!
For those who are interested on the tech that goes into making and using those heads, these heads use something called "Giant Magnetoresistance" to read magnetic fields. The trick here is they are injecting electrons of different spins between the magnetic layers separated by non-magnetic materials and depending on the field it can align those electrons to be the same spin and it manages to achieve lower resistances or higher resistances depending on what is written on the platter It is very sensetive to those fields and a lot of spin offs (pun not intended) of that promise an alternative to solid state storage. It is absolutely an amazing field i am glad i got introduced to it with my physics degree. Could write a whole conference on it and still not cover everything that we know, much less what we don't know.
The yellow stuff is urethane. Those platters are actually glass with a vacuum deposited material. Not a desiccant pouch, it's an air filter to catch any flying particles. Eventually all of the air in the drive will be pushed through that filter from the spinning platters.
AFAIK only the 2.5" ones are are glass platters, and even here, not all of them are. The recent 3.5" HDDs I tore down (oldest 2016, newest 2018) had all metal platters.
@@randycarter2001 I never checked dates as I tore them apart to recycle the aluminum. That being said, they were 40 & 80GB drives. They were probably early 2000's?
On display in my office is an old failed 80 GB IBM HHD disassembled. The headcrash had peeled away the magnetic media revealing GLASS platters! That user's data was distributed as a fine dust throughout the interior of the drive.
We made coffee tables out of ours after the surfaces were destroyed by head crashes. 2m diameter disks. A few of them managed to store a few tens of megabyes total. Enough rotational energy to roll over the 900 meter high coastal hills into the ocean.
@@volvo09 except when that price is brought down a little too far, and the whole series of drives is a complete turd [cough] seagate 7200.11 [/cough] - it's not a matter of IF those drives fail, it's only a matter of when.
I have been recycling e-waste for about 12 years now and I have taken apart 1000's and 1000's of drives. Regular Torx screwdrivers are fine. But you need a VERY well precision made screwdriver for the perfect fit on those. I have been using the same T8 screwdriver on those screws for about 10 years now. Cost me almost $20 just for the one screwdriver. Totally worth the money though.
WAY cooler video than I expected. The microscope shots were just amazing to pause and just soak up all the incredible design and manufacture. There's lots of voodoo in those devices...
Oh man, is that an understatement!!! There’s even more that goes into them now. The head itself is microscopic to the point you need a scanning electron microscope to see it. The coil to position the arms is only for rough positioning - the things on the arms Dave thought were test pads were actually the next hinge the head swings on, positioned by piezo actuators. The heads themselves fly on a cushion of air that was only 5nm thick on drives 10 years ago. (I can’t find any info on what they’re down to now.) Not micrometers, nanometers. For reference, the very latest microprocessors are made on a 5nm process. Green light is around 500nm.
I bet all the extra holes 13:06 are for a specialized tool that holds the platters in a fixture. The other holes are for the screws. When half the screws are put in the platter is turned about @ 180 degrees (or whatever it is designed for) and the other screws get put in.
I'm glad you found the grease port after removing the silver sticker! unfortunately, this one was damaged already as you clearly could hear the dry bearing. but there is still hope for other ones.
@@EEVblog That'd be proper pirate job. However, if the bearings are on their way out two things will happen: increased noise and higher han normal temps due to the extra drag. Maybe temps are not excessive as-in beyond manufacturer specs, but it's usually unswise to run HDDs beyond 40C.
I figured an automatic transmission in a car would be the most complex mechanical device most people owned. The HDD is definitely the mechanical device with the tightest mechanical tolerances anyone is likely to ever own, that's for sure.
I remember making a mobile out of old platters in high school. I've repaired computer bits and bobs before, straightened out pins, soldered wires back on, but the tolerances are so tight on hard drives, they're just beyond me haha
I recently tor down several WD Ulstrastar DC HC5120 12TB drives. They have a fused or soldered on metal hermetic seal over the screwed on face-plate because they are helium filled.
Yes, the majority will be atmospheric pressure difference, but those surfaces are pretty flat/smooth and extremely close when together, so the Casimir effect must be playing some role - maybe even a substantial role in trying to get them apart. Ofcourse, these disks are magnetised in a specific pattern so perhaps magnetism had something to do with it too?
@@MiniLuv-1984 Any sufficiently flat non-magnetic surfaces will still do the same thing. Dunno if it's Casimir effect or not but machinists/metrologists (not meteorologists, that's something else entirely ;) ) regularly use it. In that world it's called "wringing". Allows you to essentially stick two metal objects (usually things like gauge blocks) together without losing precision. e.g. if you need a 23mm gauge block you might "wring" a 20mm and a 3mm block together.
@@SomeMorganSomewhere Thanks Morgan. I've often wondered what the cause of the stickiness between two gauge blocks is. I know that two clean metals in a vacuum will weld to some extend by coming together and this seems to be an effect due to electrons migrating from one metal to the other (If I've understood the explanation correctly) - perhaps this too is responsible for wringing and perhaps the effect that Dave experienced with the disks?
In older drives that didn't unload the heads from the platters when shut down like modern ones do, they could have a condition called stiction where the heads would actually adhere to the platters because of the surface flatness, and prevent the drive from spinning.
@@RobertHancock1 Thanks Robert. I looked up stiction or static friction (only because I've only heard AvE use the word before your comment). There seems to be plenty of examples but I can't find an explanation. Will have to dig deeper.
The 2 notches at 16:31 I believe is to balance the spindle when the screws are attached. The noise should be coming from the seeking motion when the drive starts and it's looking for the index ring or something. I've not seen any more scratches on the disk like it used to when drive fails nowadays.
Looks like EDM machining, for such precision and angles available looks like good candidate. But keeps those plates, they could be lab grade in flatness.
A few years ago, I bought 4 6TB WD red drives thinking they'd be great for my new NAS not knowing they were the SMR drives. I moved ALL of my data onto these drives before I discovered the difference between CMR and SMR and was very upset that they'd put this in their red series. I contacted WD support, and they replaced all 4 of my FAX drives with the FRX drives for free. Not only that, but they sent me the drives first so I could copy my data over and requested I sent my FAX drives back after I received the FRX. There is a nearly $100 difference between the two drives, so WD essentially gave me $400 because I was a poorly informed customer... gotta say I am a WD customer for life now.
I believe the slot on the underside of the HDA is for the servo writing machine to place the embedded servo information (for proper actuator tracking) onto the platters before the controller goes in
3 ปีที่แล้ว +19
Didn't inspect the high resolution video, but i hope you don't use the biometrics of your forefinger for something important. ;)
I've always been curious about that. So it is possible to manually input the fingerprint characteristics into code or is a prosthetic made of the print?
3 ปีที่แล้ว +4
@@K-Riz314 there are several methods. In one you can make a kind of prosthetic with a laser printer (for the negative), lime for the skin simulation and graphite for the print. Sadly i don't find the video from the Chaos Communication Congress were they show how it is done. It's pretty creepy what can be done with a god camera and a photographed iris or finger.
Now take 5 from another drive, put them all on the motor, connect the leads to an ordinary BLDC ESC and rev it up! Have done that but with a smaller one many years ago and the motors in these are quite strong. But since these have FDB bearings the oil will sling out at around 20000 rpm or so (probably earlier as well) and starting to generate friction and stop. But after cooling they could work again, and you can just replenish the flung out oil with any very thin oil.
Seal looks like some kind of silicone. In the old days they used the spongey/sticky material that tend to turn into dust over time- I guess that's why they switched to silicone based seals :P
Fun fact about WD HDDs: they will show 0 bad sectors in SMART for first like 100-200 remapped bads as I remember. The only way to notice it is manually checking G-list with special software.
The head is probably made via pulver metallurgy (e.g. sintering) and then machined to final dimensions. This process makes sense for high volume high precision parts
A 1TB Maxtor that died on me around 2012 made a horrible scratching sound. It also didn't have a single dent on any of the platters. I was also dissapointed ☹ Nice informational video as always. Respects to the engineers 🙂
I feel your pain Dave.. Ah... another day, another dead WD drive. These have a habit of dying just after the warranty expires. Plug it in once, save a huge backup to it, check it, unplug, check it on another computer, unplug and into safe storage. Plug it in again a couple of years later and the drive is crunchy clicking with no hope of getting it up and running again. Tried it in various other computers and still no hope. Lucky that the data was also on a backed up to a stack of DVD+RW discs, so the data was not lost to time. The drive gets stripped down and the parts go into the scrap metal boxes.
Another dead red, red for danger as they say! All the 4tb greens I have (12 in total) made it past 60k hours and are still in use! Just bought a load more 4tb greens, might as well back a winner!
One invisible scratch that is not seen is more than enough for the servo to loose the sync with the platterns. One in one platter is enough for all to fail
Sounded like bearing failure to me, would explain the dependency on orientation for the noises. Then the motor would not reach its operating speed and the data looks garbled to the controller, hence it stops.
Could be bearings or a motor with a phase with a single shorted turn, which will mean it cannot run up to speed. Simplest test if it is a bearing is to heat it up to around 90C in the bearing area, then put the board back on and see if it starts up. The heat makes the lubricant flow again and repack the balls.
@@SeanBZA the only drives that happened too were 20/40/60 IDE 2.5 Toshiba drives. Fix was to heat the bearings with a heat gun while imaging. You never unpack anything
Normally for HDD warranties they don't go by the receipt / retail purchase date, but have an internal date based on the serial number, but looking this one up on their customer warranty submission page it shows expired 23-Feb-2021
That resistance you're feeling in the spindle motor is just back-EMF from the brushless motor acting on the permanent magnets in there. Fun fact; you can connect the terminals of that motor directly to a standard hobby aircraft/drone brushless DC motor ESC to get things spinning real quick!
@@paulcohen1555 hmm... I think you're right. Although when I spin a brushless permanent magnet motor that's disconnected, there is still a 'cogging' effect where it clicks. What causes that?
@@LazerLord10 The rotor is essentially a multi-sectioned magnet and the stator is made of sheets of laminated steel (referred to as a slotted stator). Since the stator is magnetic the rotor will "cog" to one of the positions. Most BLDC stators are typically constructed with anywhere from 2 to 6 "pairs" and you can count them based on the number of cogging positions of the rotor.
SMR drives aren't bad per se but they definitely have preferred use cases, those being archive or sequential transfers of very large files. If you're trying to use them as a system drive in a desktop or something else with frequent random writes you're in for a bad time. Ideal use in a desktop would be combining an SSD for operating files and a large-capacity SMR drive for storage of media files that don't change much.
Platter screw was probably an ip7, torx plus #7. We used those in cell phones, they are able to take higher torque without stripping the head. Normal torx can be used, but is not the preferred tool for them. Torx plus drivers will not fit torx screws at all.
From my experience taking apart 1,000's and 1,000's of these, it's a T8. But you need really precise screwdrivers. The one I use for the platters is a T8 and it cost me about $20. Just for the one screwdriver. If you spend less money, there will always be some play and they will always strip. I found that out the hard way when I first started my computer recycling business about 12 years ago.
@@markjohnson7887 That's my experience, too. So easy to strip the head and damaged the bit at the same time if you're not careful with the trigger on the impact driver. When I line up a whole lot on the bench and get a good rhythm going, I can do about 2-3 screws a second.
If the other 3 drives were approaching being full and they are not in any way duplicate of each other, it is more or less impossible for a 4th "redundant" backup. This could be technically possible if the 4th was compressed and the other 3 had compressible data. If like there were 2 sets of duplicates of 2, yes. The 2 scrapes on the edge of the ring were probably balance adjustments.
Contaminations and imperfections on the disk platters might not be visible with normal light. If you care enough you can use "green light" to check for damage. See th-cam.com/video/lYHeFJf11Mo/w-d-xo.html for more information.
Dave, the so-called death clicking is not usually caused by problems on the surface of the platters. Mostly, it comes from either head assembly problems or platter motor problems. As you mentioned, tolerances are extremely small, so if heads can't move properly or platter rpm isn't spot-on, the drive's controller enters a loop trying to seek valid signal(or data - I'm not exactly sure whther it's the actual onboard controller of the HDD or the motherboard). At least that's what I remember from university :) There is another type of click, which is more rhythmic, and very loud - that's if there's issues in the signal path of the heads so they don't get any feedback off the tracks. The servo then launches them to the middle and they hit hard and click. But that's not what you hear here. By the way, if u listen carefully, when you spin the drive open, there is a specific sound when the heads passed over the scratch you made - that totally destroyed the head :) Oh, one more thing - those notches on the platter shaft I think are weight balancing holes so that the center of mass is exactly in the middle.
The hollow traces on the head could be thermal insulation, so that the chip-on-flex does not desolder. The traces are broader than the others, so the may carry the current for writing, perhaps? What do you think?
I'm impressed that at @8:26 just after taking off the top that you've already got visible dust specks on it (upper right corner, and upper left corner near the middle of the platters). Just goes to show how important clean room facilities are due to how quickly it can become contaminated.
should always try getting an identical used model on ebay. switch out the circuit board and you just saved your data. ..and you still have one left to tear apart :)
Dismantled quite a few old hdd for Magnets Made a small grinder out 1 stuck some fine sandpaper on the disk other than that the case use for a mount etc or scrap
One time I gave a friend a pair of hard drive magnets to play with - it was all fun & games until put them in his pocket. The moment they slide down inside his pocket it pinched his skin on his leg so bad it became bruised and bit bloody. Never again did he put magnets in his pocket.
and we are all paranoid about getting a magnet close to a hard drive,,, and yet the disks spin past the servo magnet cage at 5400 7200 10000 15000 rpm....
So a trick to recover data from a failing hdd, put it is a zip lock bag remove as much air as you can (vacuum seal works too) and place in your freezer for a couple of hours. Sounds funny I know, but you would be amazed. As for the pressurized hdd's, I think WD had a some that were "filled" with helium. Though I couldn't understand why. As helium leaks through everything, even glass.
I had 8 of these in a NAS, they all failed within 2 years. I used to be a loyal WD purchaser (small computer building business) but use HGST when I can't find a flash solution at a good enough price.
Last 3 weeks 4 out of the 5 wd 6TB HDs failed in my nas. Had to replace all of them. All cmr versions with 30-40k hours on them. Replace 1, test, rebuild, fail another, backup all with raid in fail mode and 1hd with bad blocks. Create new raid, fail another disk after successful test. Hell of a week.
For those who still own old, really old VHS, or especially Betamax video-recorders, yes, the precision is not as great as a modern HD, but they are a far more 'mechanically' complex device than this HD by a mile. As for precision, until the day that higher density hard-drives become the norm in homes, actually the VHS & Video-8 / Hi-8 video heads were the most accurate precision machined device consumers ever owned.
The bearings used for the head actuator and spindle motor must be built to a very high standard and tight tolerances, There's no room for any wobble or run out on a hard drive, and they have to be able to remain essentially play-free throughout their lives.
![[Full Episode] The Restaurant War Thailand ศึกพ่อค้าซ่าแม่ค้าแซ่บ Episode 2 | 29 ก.ย. 67](http://i.ytimg.com/vi/r3lfLNH6Ke4/mqdefault.jpg)
I just remembered, I still have a dead 4TB WD RED drive sitting on my desk (it is from the same series as yours and is a couple of months newer), it failed on me last year.... I should pull it apart too (that is why it is sitting on my desk, I was going to do a video on it one day!), my drive is from 6th March 2018 and it is also an EFRX version.
Maybe you'll get lucky and get all groovy.
there are places that do PCB swaps on these for cheap, often the WD PCBs fail when the drive is mechanically fine. FWIW if you wanted to try and recover the data
Platters are perfect coasters for your Cup or Glass ;-)
@@oggyosbourne You could stick it on your forehead and pretend to be a doctor from 1960s? What was that all about?
@@MrMaxeemum The head mirror acted like a ring light. The forehead position is basically parked; in use it was worn over one eye. A bright light source to the side of the patient gave the doctor a better view of the patient's ear, nose and throat. Of course we've had better tools for the job since the 1930s, but head mirrors were so iconic in the days of silent film that they became a costume trope.
27:19 And that's where he discovered he had pulled out the wrong drive, and the defective drive is still in the NAS :P
💀
Hahahahaha!
Curious Marc can still fix this drive
@@roelandriemens no way he could fix it
He could hear the drive sounds...
Actually in the old big (physical size) drives the head activator look like the coil in a huge speaker and was called "voice coil".
Working out that area was really dangerous because it could easily cut your fingers if you were in it's way.
The high capacity drives are filled with helium, that is in order to be able to hover the heads closer to the surface of the platters than atmospheric air allows.
The breather hole is needed on non-helium drives because the turbulence when the drives spin up, compresses some of the air, which causes lower pressure on top of the platters, causing the heads to hover too close, so when spinning up, they'll suck in air to compensate (over simplification), the helium drives have a slight over pressure to compensate for this.
The white pad is a filter, designed to collect contaminations thrown off the platters. however, activated charcoal filters, and desiccant is common to find also.
Regarding the screws, this is very common, i think they use custom sized torx, as i have experienced this many times.
The trick is to loosen the screws one by one, and re-tighten them before going on to the next, if you loosen all screws at once, the last screw will carry so much load, that it can be hard to remove.
The various aluminum parts are nickel plated, that is why they have a texture that could look like cast some places.
Actuator arms have been both machined and cast over the years, but cast is more common in older drives.
The head parking feature is used on all HDDs today, because of the flatness of the platters and heads, they will actually stick if they ever contact the platters, so the heads can't rest on stationary platters like they did years ago.
Another fun fact, to ensure the heads are parked in case of power failure, it actually uses the platter motor as a generator, to generate just enough power to return the actuator home, before it is spun all the way down.
so that's what those traces were, splitting off at the motor, going into the case?
Helium is a good heat conductor.
@@Inertia888 Nope, the 4 motor traces probably go straight to the windings with electronics choosing the energy direction. On the head cable, there'll be fat traces to the speaker coil and to the chip power pins, while the thin traces carry data and perhaps control.
15:06 That window is used for writing the servo track during production.
PS: I have been working for 4 years at Quantum Corp.
Have always wondered about that since it just didn't made any sense but now it do, thank you!
My first thought was that it would be for writing initial data. Thanks, James! I like Quantum. Been around for a long time. Pioneers. (I built the iRobot B21R's).
I thought those would be written before assembling the stack, then ignored on the surfaces that don't need it. Or maybe written by the main head in a special firmware mode that starts by finding the extreme head positions, then step the actuator according to a precomputed curve or sensing the last written servo track weakly as it chooses the next track location (such an algorithm would result in slightly different track counts between drives, hidden by firmware from the logical interface view).
12:17 I’m pretty sure that’s just the recirculating air filter. Any little bits flying around will be carried along the outside of the platters and get trapped there
Air filtration. And the bottom access (removed sealed label/tape) is to write/read rom sectors to drive at manufacturing (boot/block, servo information, etc). Many drives have the factory access on the side (sealed label/tape). Been awhile since I took a recovery class under Scott M. of MyHardDriveDied ... look him up...great resource here in the states.
Yeah, if you have ever opened a laptop HDD that had a serious head crash you can usually find all your data on that filter in dust form.
@@DONK8008 It's entropy-encoded data.
I think your diagnosis that it has crashed is incorrect.
The head positioning is done via feedback from the read signals from the heads, either a single servo head or (in this case) embedded servo information on all heads.
There has been a failure in the read amplifier and thus the head servo has lost control, and that is what you see and hear.
When you view videos from people who know how to recover these, you will see them replace head assemblies and make them work again (at least to read the data).
Well yeah, obviously. But it sounded bloody horrible before I took it apart and found there was no head crash.
Agreed. The noise heard was the continuous seeking due to head or board failure, rather than heads coming in contact with the platters. It’s good to know that most likely the data could have been easily recovered with just a board or head swap. Now if this would have been a Seagate drive….
@@ecaparts Could have been the arm the heads are attached to smashing into the center as well. I have seen that happen more than once. Makes a nasty noise.
My guess is that head contact would have a more consistent frequency. Either a steady screech or something synchronous with the platter rotation. The sound you played was more stochastic, consistent with your conclusion and others that it was seeking gone wild.
i thought the motor slowed down too quickly after dave spun it. i thought the motor or bearings may have failed.
The heads are created in layers using the same processes used for semiconductor chips. They go through thousands of operations to build a three dimensional structure using exotic materials (platinum, tantalum, gold, copper, diamond-like-carbon, silicon carbide, etc.). They are oriented vertically (standing on edge), so that thousands can fit onto a single wafer. The crazy part is that they have machines with enough precision to mechanically separate them from each other, with the air bearing surface still in tact (it is not simply a smooth surface).
@@artdehls9100 most of the tools combine photolithography with physical vapor deposition, chemical vapor deposition, ion beam deposition, ion beam etch, electro plating, chemical mechanical polishing. It's all built up in layers. It takes many layers to build one physical feature because the processes have limitations with the geometries they can produce, so the material (wafer) goes back and forth from tool to tool. You may build up a layer only so it can be sacrificed later by some other process that can't differentiate what it should remove from what it should keep.
The tools themselves vary wildly in appearance. If they use a vacuum they maylook like large stainless cylinders with lots of plumbing on the outside and a robot arm on the inside.
I've seen some that look like washing machines.
Others look like Rube Goldberg machines.
@@artdehls9100 the coil on a hard drive head is embedded in other materials. For cd readers it's probably different
In my experience, actual physical head crashes are extremely rare in modern hard drives (especially with 3.5" form factor drives) and the failure mode is almost always down to corruption of the embedded servo data, resulting in the drive being unable to track properly, or a problem with the drive electronics - the hub motor / head actuator drive chips often get very hot and are known to fail. The motors themselves very rarely give problems, so if a hard drive won't spin, it's usually going to be an issue on the PCB. Chattering heads (the actuator arm banging back and forth between its travel limits) is often caused by bad servo data, in which case there's not usually much that can be done to correct it. Total failure of the drive to be detected by the operating system is invariably the main onboard microcontroller/DSP chip and intermittent detection failure is usually just bad cables/connectors.
The little "bag" which you thought was a dessicant pack is actually a filter designed to trap any particles that get thrown off the surface of the platters - thses things are generally spinning at between 4000 and 8000 rpm and thus any dust and debris that lands on them will be hurled off at high speed due to centrifugal force - as a result, opening the hard drive in a non clean room environment is nowhere near as damaging as popular myth would have us believe - I've done it many times, particularly on certain laptop drives that have a habit of sticking (I'm looking at you, Samsung) without any problems, and many of those drives are still working years later (9 years and counting for one of my own drives). I wouldn't recommend it of course, but if you absolutely have no other options available to get a drive fixed, then it's not something you should be totally paranoid about, as it is entirely possible to get good and reliable results from this procedure. Obviously you should work in as clean an area as possible, using minimal air circulation (turn the desk fan off), keep your fingers and any tools off the platter surface and try to get the job done and the drive closed up again as quickly as possible.
(and try not to let your inevitable sweat drip onto the platters - that's never going to end well :) )
Thanks for this info. I’ve long suspected that head crashes are actually spectacularly rare, likely only to happen as a result of severe shock during operation (like in a dropped laptop, especially in the days before the drives had accelerometers that told them to park the heads as soon as a drop was detected).
I had to LOL when Dave speculated the pads on the lid were to cushion the platter in case it wobbled... I guess he doesn’t know how insanely small the fly heights on hard drive heads are. (I suspect the pads are to dampen noise and vibration, but this is pure speculation.)
My vague recollection is that it's not necessarily unsalvageable, just difficult- the tracking data just spontaneously becoming unreadable without any signs of damage is unlikely, and the reason it can't find it, is that something up the chain has failed-heads, flex, amps, etc.
Not something easy to fix though- would likely need donor parts with the exact same serial number, and even then there can be different versions.
So you'd be spending at least as much as you paid for the drive to fix it just on parts.
Not a simple swap either, as there's some level of data on those boards that needs preserving, component level repair is the easier option.
The data is untouched, but the information is gone- without the way to properly interpret it, it's just noise
My experience matches yours. Additionally, in my experience a head crash (i.e. when the read/write head makes physical contact with the platter(s)) results in a scratching sound, rather than a click. The so-called "click of death" is actually the armature constantly resetting (as seen in the video).
We pull out head crashed 15k 2.5" drives all the time from the datacenter, almost all of them that suddenly died (instead of g-list getting full) are of that kind
Just looked up their Dutch address printed on the case and yep it's one of those tax dodging buildings. You can look the street name up Taurusavenue 5 Hoofddorp. That whole building has thousands of companies registered in The Netherlands so they pay like 0.1% Tax while they virtue signal on Twitter how much they care.
Coil doesn't need feedback as they use servo info written on the surface of 1 platter
Yes, I figured that's the only way they could do it. But then you have a chicken and egg, so it would require the servo markers already written before first start up. So maybe that's what that bottom slot is for at production?
I came to ask this! Perhaps back emf can give some positional info, too?
@@EEVblog Servo tracks were written on a separate machine back when I was working on drives. Self servo writing is something that has been looked into, But I don't know if its currently being done.
Dedicated servo track platter is prehistory ;-) Modern HDDs use embedded servo, i.e. servo data interleaved with the actual data sectors since eons now.
@@KernArc How do they get it on the plater in the right location during manufacturer?
Used to love taking apart hard drives as a kid. It really felt miraculous, even in the 90s, to have such a precisely made machine in your hands. It's actually a little surprising how superficially similar a modern unit looks to one of those old ones, though I'm sure the engineering has only gotten more advanced.
It is amazing, given how much tech goes into these things, how really inexpensive they are.
Yeah thanks to China!
@Stop Banningme Nope.. Humans at all is too expensive and too clumsy.. This is pretty much machine only cleanroom stuff...The benefits of mass production. Also you can look at drives from different manufacturers, and see how incredibly similar they are. screws in the same spots, castings are identical etc...
@@blitzwing1 I think you’re being facetious at the beginning there... and I certainly hope so... because there are _so many_ things wrong with no-holds-barred capitalism, I don’t even know where I’d begin if I thought I had to explain it here. :)
@Stop Banningme No.. you don't need people to run machines... The factory of tomorrow is without humans... Robots who build robots, AI doctors etc... What a wonderful world.
Made in millions...
5:00 That red potting compound or whatever is telling "I'm sorry Dave, I'm afraid I can't do that."
5:30 Traces used for the electroplating that were then cut, I assume?
26:40 Gauge platters, I reckon. Perfectly wrung together.
*17:06* _The coil is an _*_orthocyclic_*_ (non-helical) winding, onto a sector-shaped bobbin._
_You can see the uneven step-over zone of the coil, nearest to the heads, where each loop of wire jogs to the next adjacent winding plane._
For a bigger hard drive Teardown and much younger Dave. Eevblog # 395.
Dave thanks for keeping Andy @PhotonicInduction inspired and his spirits up. A lot of people including myself were quite worried. God bless.
The two machined semi circles on the platter hub are almost certainly not for a holding tool but are a balancing operation done post assy
Dead Red Revolver? I'll see myself out.
If your re-assemble the magnets and drop one of the aluminium rings between them, you can see Lenz's law in action as the ring moves much slower than you would expect.
The first time I dropped a spherical magnet through a non-ferrous tube was... a treat of wonder. :)
ah we just did a bunch of Lenz's law in physics today
@@DavidLindes , that is one of the great wonders of the modern world that wasn't around when i was a kid. i have a copper water pipe in this very room i'm in as i type this and a stack of super magnets that snugly slide down the pipe. and whenever i come across more magnets of that diameter i add them to the stack and they slide down the pipe even slower.
@@vsvnrg3263 nice. :)
I'm sure others have pointed out that with modern drives just changing the torque on the screws on the top plate is enough to cause them to fail. Then you get into the helium filled drives...another story all together.
No doubt
The helium filled drives have a 5 year lifetime, if you have not replaced all drives after 5 years (does not matter if they are powered on or off the helium is still leaking away) enough of the helium will eventually leak out for the vacuum that is left to weld all the heads to the platters. For the hard disk manufactures it is the ultimate in planned obsolescence. It would be a bit like buying an engine with a very miniscule oil leak where you can not replace the oil, once all the lubricating/cooling fluid has leaked away bad stuff happens.
@@itsevilbert Thanks for the heads up. Will steer clear away from He
@@addydiesel6627 largest air filled drive is a 10tb Toshiba Drive, they where somehow able to cram 7 platters in the standard 1 inch high casing without needing to use He. The maximum platter count for air filled drives has been 6 for eons, I have a 18gb quantum SCSI drive from 1999 and that has only 6 platters, again in a 1 inch high case.
@@addydiesel6627 For data centres they make total sense, long term data is backed up to tape, and failed drives are hot swapped with new drives minutes after a fault. Helium is less viscous than air and has better cooling properties so the drives can spin faster (quicker access time).
And as for SSD's they are worse for long term data storage when compared to helium filled drives "if powered off" ( See "Temperatures and data retention" in www.jedec.org/sites/default/files/Alvin_Cox%20%5BCompatibility%20Mode%5D_0.pdf the data is from Intel), after about a year powered off the data on Consumer grade SSD drives starts to fade away, on Enterprise grade drives data starts to fade away after about 10 weeks powered off! SSD's are not designed to be powered off for long periods of time. Nothing lasts forever though, so it is all about understanding the limitations of each new technology and how that fits into your own personal requirements.
It's actually not just a desiccant packet. That is the micro particle catch. If something were to get into the drive, it would get flung into that catch.
But there is an filter and desiccant packet near the vent hole.
@@paulcohen1555 You do realize there is ventilation hole right? So the desiccant pack would be fully saturated with moisture by a few days to weeks on a product that is supposed to last years therefor rendering it useless?
@@marksnow8838 But there there isn't a fan behind that hole.
It's just to equalize small differences in the pressure.
And it's doing a good job when the drive is kept at a constant temperature.
@@paulcohen1555 So what's up calling it a "vent hole"? Regardless a hole allows moisture to seep in, so if its a desiccant pack(which its not), then it would be fully saturated with moisture within a short time span.
Anyway the hole at the bottom of the drive is mainly for pressure equalization caused by weather changes, altitude changes, temperature changes etc. The filter beside the platter is to catch any remaining particles after assembly or would be generated during the operating lifespan of the drive. The platters still moves air even though its not shaped like a fan.
That is why you need multiple filter in a hard disk.
Exactly. At 5400 or 7200 RPM, the spin of the discs create a whirlwind of sorts that flow through that micro filter catching any small particles.
The platters make nice wind chimes.
Unless they’re glass (Death Star drives) 😂
I had one as shaving mirror for a couple years :D
But they'd all be the same note - you'd need different platters from different drives, and even then, they'd probably have a very similar pitch to them. I bet all the platters are nearly identical in every drive.
They also work good as a signaling mirror. 👀
I have a stack of old platters that I use as mirrors. They are the perfect size to see the I/O on the back of an audio amp or preamp.
The small square bag in the corner is a air filter, the shape of the chamber gives you a clue, the air movement from the platters draws a little air through it as the drive spins.
The separation plates between the platters are there to reduce the amount of air that moves across the faster moving edges of the platters, to reduce drag.
Quite often in smaller drives the platters are made from glass with a coating applied by vacuum deposition.
I'd wondered if that was what the plates were for - thank you for confirming it.
The pads are airfilters for any minuscule particles that sneak in during production.
+1. There might be some desiccant in there, but the spinning platters create airflow across these pads to ensure that any speck of dust is contained. Dust = warranty replacement.
If you cut one open they're filled with black smoo, presumably carbon
@@_BangDroid_ activated carbon would be quite logical
@@666Tomato666 Yup, that's what it is. And I have taken apart hard drives where they ripped open during operation. It's really, really messy. lol
That white "pillow" at 12:18 is not a desiccant it is there to trap microscopic particles, i.e. from the platter coating, which wears off over the years (makes bad sectors and weak/damaged heads). If you had a head crash you would probably see lots of grey platter dust on that white filter (some platters are just glas discs with a special magnetic coating (nickel alloy ?).
ps2, i saw somewhere that the coating may be ruthenium. there are probably other less exotic substances used now. i dont know of any other use for ruthenium.
Just want to say to everyone, that drives today from any manufacturer are pretty damn robust. They are machined to really tight tolerances and some have the ability to park the heads before physical damage can occur by detecting the G forces applied to the drive. So the damage is less likely to be physical scrapes on the platters unless you've really dropped the drive or given it a jolt. Desktop drives are more easily physically damaged from movement but desktops are less likely to be moved. But really, the most likely failure point for any non-physically damaged drive are the pressure pads that let the signals travel between the board and the motor and heads. At least that is what I've found to be the case.
The pressure contacts eventually begin to put less and less pressure on the pads over time and they also eventually start to oxidize, both problems create higher resistances in the connections and that eventually causes issues spinning the drive, moving the heads and reading/writing the data. If you are placing a drive in a freezer to get data off and it's working then those pressure contacts are likely the reason why your drive is failing. I've seen the pads for the head connectors oxidize causing read/write issues and I've seen the pressure connection pins for the motor connector loosen enough over time that the platters won't spin up properly or even at all. Physically cleaning oxidation and bending the pins for the motor connector to make more pressure on the pads is usually enough to give a drive some life support but if you want reliability then it might be necessary to replace any aged pogo style connectors that are going to the head assembly. [... _or just replace the pressure connectors with some carefully made direct wired connections and live a happy life with an _*_almost immortal_*_ drive_ ...] And I've never had to, but if you use something like Deoxit then only use it on the board side and not the mechanical side, or at least be careful and don't spray anything at it. Just use a q-tip or cotton swab and don't get anything inside the mechanical part...
I've also seen shorted protection diodes on boards but that seems more likely an issue on external drives and less likely on internal drives unless the power supply is going out or you've got some fancy pants removable drive system. And they really need to add some protection diodes on all power rails right over the motor driver and maybe even the DSP chip, too. Faulty power connections occasionally destroy those things.
at 4:35 was hoping for closer inspection of pads followed by clean and retry.
I doubt “most complex mechanical product” applies. But “Most precisely engineered mechanical device” Definitly applies.
your cpu be like: am i a joke to you
@@iliandocx8392 That's where you get into semantics of what is mechanical or not (like does it need to have moving parts)
If it's most complex device full stop, then yeah it is UNDOUBTEDLY the CPU
Actually basic design of hdd kept the same for 20 years. Just endless polishing of technology.
Well yeah, but what makes them impressive is all the little details that are needed to make it work not the broad strokes.
Yes, that drive looks remarkably simular in every aspect of the mid 2000 WD's I have opened up over the years
Holes near the read amp have small traces going to them - may be for the gold plating process - connecting all the copper together, then punched out after plating
Also could be used for automated testing when the motor is being made to check resistance and inductance and probably ground leakage, gets trimmed off later
.
Or fex last step to open some very sensitive stuff up from shorting them to ground due to ESD reasons. there might be a reason it just at the head assembly.
The big bras "test pads" up near the heads are actually pietzo crystals. apply voltage moves the head left and right. its the fine adjustment to the servo.
Dave, maybe consider running different manufacturers or batches of drives in NAS(unless RAID0). I got WD+Seagate combo, probably not matched in performance, but will not fail all at the same time.
Unlikely to all fail within days of each other.
@@EEVblog you think? Had 3 out of 4 6Tb WD Purple drives fail within 2 weeks in a couple of DVRs all installed at the same time and sequential serial numbers...
You're right about them being the most mechanically complex device most people own. The tracks in a modern drive are something like 50 nanometers wide, and the fly height is about 5nm (similar scale to modern CPU transistor size). A modern drive has about 400,000 tracks, and the heads can seek to the right track in, usually, less than 10 milliseconds. Truly incredible.
No visible damage to your platters, in which case it may have been a bad head or bad head pre-amp. The drive has a service area which contains parts of the firmware that are needed for the drive to work. If the drive can't read that area on startup (bad head, preamp or scratch in the SA) then it will just start clicking (seek re-tries as it tries to find the SA tracks).
Could be various other things of course.
The first video I watched on your channel was the teardown of a HDD that was probably 1 millionth of the capacity of this one
sorry for my poor English,
the window on the back is actually a hole for "servo writer" to lock and guide the arm to initialize the hard disk like "low level format". You don't see that window on very old hard disks because they use step motors to locate each tracks. but the new hard disks use voice coil to move the arms, the voice coil won't really locate tracks if the disk platters don't have the "servo tracks". therefore the new hard disks need a servo writer to hold the arm through the window you see on the back, and guide the arms for the write heads to write the initial servo tracks just like "low level format".
Dave, you should know that those metal flanges are being connected by a non-reversible tremie pipe to the differential girdle spring on the “up” end of the grammeters.
Also, I wonder if you can "lift" finger prints from that glorious 4K video?
I remember the first time I took 1 of my old dead HDD's apart and scavenged the magnets etc out of the thing
Yeah, did my first one as a kid and i thought i had discovered the strongest magnets on the world :)
They make excellent fridge magnets for thicker or heavier things.
@@volvo09 The first time you accidentally snap them together and you get a blood blister. lol
The full-height SCSI drives have magnets that are about 4x as thick. I managed to scavenge about 20 of them. Very handy. Also quite dangerous.
Ah yes, I too remember the pain of an out of nowhere pinched finger lol.
Also, be careful with laptop hard drives as they often have glass platters, a friend found out in a surprising way when the patter exploded as he was taking it out with a screwdriver and applied a bit too much force.
This where you come to find that a capacitor in the circuit went open and was causing undesired oscillations causing the heads to miss align and not boot!!!!
For those who are interested on the tech that goes into making and using those heads, these heads use something called "Giant Magnetoresistance" to read magnetic fields.
The trick here is they are injecting electrons of different spins between the magnetic layers separated by non-magnetic materials and depending on the field it can align those electrons to be the same spin and it manages to achieve lower resistances or higher resistances depending on what is written on the platter
It is very sensetive to those fields and a lot of spin offs (pun not intended) of that promise an alternative to solid state storage.
It is absolutely an amazing field i am glad i got introduced to it with my physics degree. Could write a whole conference on it and still not cover everything that we know, much less what we don't know.
The yellow stuff is urethane. Those platters are actually glass with a vacuum deposited material. Not a desiccant pouch, it's an air filter to catch any flying particles. Eventually all of the air in the drive will be pushed through that filter from the spinning platters.
I recently "trashed" 30 or so drives. The platters bent, they didn't shatter like glass.... The coating crazed but they didn't shatter.
@@paulravitsky2898 That is correct, some have glass platters, others simply use an aluminium alloy with magnetic coating.
@@paulravitsky2898 How old were the drives? As of 2016 Seagate was using glass platters.
AFAIK only the 2.5" ones are are glass platters, and even here, not all of them are.
The recent 3.5" HDDs I tore down (oldest 2016, newest 2018) had all metal platters.
@@randycarter2001 I never checked dates as I tore them apart to recycle the aluminum. That being said, they were 40 & 80GB drives. They were probably early 2000's?
On display in my office is an old failed 80 GB IBM HHD disassembled. The headcrash had peeled away the magnetic media revealing GLASS platters! That user's data was distributed as a fine dust throughout the interior of the drive.
We made coffee tables out of ours after the surfaces were destroyed by head crashes. 2m diameter disks. A few of them managed to store a few tens of megabyes total. Enough rotational energy to roll over the 900 meter high coastal hills into the ocean.
I have a SAS drive where all 5 platters were pretty-much transparent. What a mess inside that one was.
What amazes me is how they can produce such high precision so cheaply. They can print silicon, but they can't print hard drives!
Yeah, SSDs are cool and all, but HDDs are a marvel of precision engineering and manufacturing brought down to a price.
@@volvo09 except when that price is brought down a little too far, and the whole series of drives is a complete turd [cough] seagate 7200.11 [/cough] - it's not a matter of IF those drives fail, it's only a matter of when.
silicon is not printed :/
@@adredy I was speaking metaphorically.
those platters make excellent mirrors for laser projects.
Hey Dave, those screws may be Torx Plus not standard Torx.
I have been recycling e-waste for about 12 years now and I have taken apart 1000's and 1000's of drives. Regular Torx screwdrivers are fine. But you need a VERY well precision made screwdriver for the perfect fit on those. I have been using the same T8 screwdriver on those screws for about 10 years now. Cost me almost $20 just for the one screwdriver. Totally worth the money though.
@@markjohnson7887 what brand do you recommend for precision bits? or what brand is that torx?
@@runforitman Wiha and PB Swiss are very good.
@@markjohnson7887 , 1000's of drives? do you save magnets like me? do your kids think youre the best dad on the whole earth?
I still remember the time when they said that with conventional magnetic recording, no platter could hold more than 80GB
WAY cooler video than I expected. The microscope shots were just amazing to pause and just soak up all the incredible design and manufacture. There's lots of voodoo in those devices...
Oh man, is that an understatement!!! There’s even more that goes into them now. The head itself is microscopic to the point you need a scanning electron microscope to see it. The coil to position the arms is only for rough positioning - the things on the arms Dave thought were test pads were actually the next hinge the head swings on, positioned by piezo actuators. The heads themselves fly on a cushion of air that was only 5nm thick on drives 10 years ago. (I can’t find any info on what they’re down to now.) Not micrometers, nanometers. For reference, the very latest microprocessors are made on a 5nm process. Green light is around 500nm.
White small pillow is air filter, not moisture absorber.
I bet all the extra holes 13:06 are for a specialized tool that holds the platters in a fixture. The other holes are for the screws. When half the screws are put in the platter is turned about @ 180 degrees (or whatever it is designed for) and the other screws get put in.
I'm glad you found the grease port after removing the silver sticker! unfortunately, this one was damaged already as you clearly could hear the dry bearing. but there is still hope for other ones.
I should fill my other drives? Will axle grease do?
@@EEVblog Silly question, of course you use WD40, as you do for everything else 😉
@@cornflake75 Hence the name WD40. It came with the first WD drive back in the days.
@@EEVblog I think elbow grease is the right kind
@@EEVblog That'd be proper pirate job. However, if the bearings are on their way out two things will happen: increased noise and higher han normal temps due to the extra drag. Maybe temps are not excessive as-in beyond manufacturer specs, but it's usually unswise to run HDDs beyond 40C.
I figured an automatic transmission in a car would be the most complex mechanical device most people owned. The HDD is definitely the mechanical device with the tightest mechanical tolerances anyone is likely to ever own, that's for sure.
I remember making a mobile out of old platters in high school. I've repaired computer bits and bobs before, straightened out pins, soldered wires back on, but the tolerances are so tight on hard drives, they're just beyond me haha
And pretty much everyone else. :-)
I recently tor down several WD Ulstrastar DC HC5120 12TB drives. They have a fused or soldered on metal hermetic seal over the screwed on face-plate because they are helium filled.
Oh no, you didn't take apart the spindle motor. It would have been interesting to see the engineering that goes into spinning all those platters.
It's basically a 3-4 phase brushless motor with hall effect sensors. They tend to be press/thermally fit and virtually impossible to take apart.
@@Segphalt "virtually impossible to take apart."
That sounds like a perfect reason to stick @EEVblog onto it. Watch Dave wrestle with the thing!
@@PeterUrbanec Though some of those motor models aren't individual pieces as the stator is designed as a part of the HDD chassis.
@@Segphalt no, there aren't any hall sensors, as there is no way you can feed them and the coils with just 4 contacts.
probably the most interesting bit is the hydrodynamic bearing. I haven't yet sliced one apart, i probably should.
The platters are usually coated glass, they will break like glass, and that's how they get the finish ;)
Almost like Casimir effect when you put those platters together -- but it's just atmospheric pressure at work :-)
Yes, the majority will be atmospheric pressure difference, but those surfaces are pretty flat/smooth and extremely close when together, so the Casimir effect must be playing some role - maybe even a substantial role in trying to get them apart. Ofcourse, these disks are magnetised in a specific pattern so perhaps magnetism had something to do with it too?
@@MiniLuv-1984 Any sufficiently flat non-magnetic surfaces will still do the same thing.
Dunno if it's Casimir effect or not but machinists/metrologists (not meteorologists, that's something else entirely ;) ) regularly use it. In that world it's called "wringing". Allows you to essentially stick two metal objects (usually things like gauge blocks) together without losing precision. e.g. if you need a 23mm gauge block you might "wring" a 20mm and a 3mm block together.
@@SomeMorganSomewhere Thanks Morgan. I've often wondered what the cause of the stickiness between two gauge blocks is. I know that two clean metals in a vacuum will weld to some extend by coming together and this seems to be an effect due to electrons migrating from one metal to the other (If I've understood the explanation correctly) - perhaps this too is responsible for wringing and perhaps the effect that Dave experienced with the disks?
In older drives that didn't unload the heads from the platters when shut down like modern ones do, they could have a condition called stiction where the heads would actually adhere to the platters because of the surface flatness, and prevent the drive from spinning.
@@RobertHancock1 Thanks Robert. I looked up stiction or static friction (only because I've only heard AvE use the word before your comment). There seems to be plenty of examples but I can't find an explanation. Will have to dig deeper.
HD... relatively simple principle (almost like vinyl) but with crazy production engineering to achieve multi-terabytes.
The 2 notches at 16:31 I believe is to balance the spindle when the screws are attached. The noise should be coming from the seeking motion when the drive starts and it's looking for the index ring or something. I've not seen any more scratches on the disk like it used to when drive fails nowadays.
Looks like EDM machining, for such precision and angles available looks like good candidate. But keeps those plates, they could be lab grade in flatness.
A few years ago, I bought 4 6TB WD red drives thinking they'd be great for my new NAS not knowing they were the SMR drives. I moved ALL of my data onto these drives before I discovered the difference between CMR and SMR and was very upset that they'd put this in their red series. I contacted WD support, and they replaced all 4 of my FAX drives with the FRX drives for free. Not only that, but they sent me the drives first so I could copy my data over and requested I sent my FAX drives back after I received the FRX. There is a nearly $100 difference between the two drives, so WD essentially gave me $400 because I was a poorly informed customer... gotta say I am a WD customer for life now.
I used to dismantle lots of server harddisks to get the magnets out, they are extremely useful.
It's highly unlikely that part is cast. The draft angles would be an absolute nightmare.
They're pretty much all cast these days, with only a few small machined surfaces.
Never mind, thought you were referring to the main body, not the head.
I believe the slot on the underside of the HDA is for the servo writing machine to place the embedded servo information (for proper actuator tracking) onto the platters before the controller goes in
Didn't inspect the high resolution video, but i hope you don't use the biometrics of your forefinger for something important. ;)
I've always been curious about that. So it is possible to manually input the fingerprint characteristics into code or is a prosthetic made of the print?
@@K-Riz314 there are several methods. In one you can make a kind of prosthetic with a laser printer (for the negative), lime for the skin simulation and graphite for the print.
Sadly i don't find the video from the Chaos Communication Congress were they show how it is done.
It's pretty creepy what can be done with a god camera and a photographed iris or finger.
Now take 5 from another drive, put them all on the motor, connect the leads to an ordinary BLDC ESC and rev it up! Have done that but with a smaller one many years ago and the motors in these are quite strong. But since these have FDB bearings the oil will sling out at around 20000 rpm or so (probably earlier as well) and starting to generate friction and stop. But after cooling they could work again, and you can just replenish the flung out oil with any very thin oil.
Seal looks like some kind of silicone. In the old days they used the spongey/sticky material that tend to turn into dust over time- I guess that's why they switched to silicone based seals :P
Fun fact about WD HDDs: they will show 0 bad sectors in SMART for first like 100-200 remapped bads as I remember. The only way to notice it is manually checking G-list with special software.
The head is probably made via pulver metallurgy (e.g. sintering) and then machined to final dimensions. This process makes sense for high volume high precision parts
A 1TB Maxtor that died on me around 2012 made a horrible scratching sound. It also didn't have a single dent on any of the platters. I was also dissapointed ☹
Nice informational video as always. Respects to the engineers 🙂
and now assemble everything back ! :D :D
I feel your pain Dave.. Ah... another day, another dead WD drive. These have a habit of dying just after the warranty expires. Plug it in once, save a huge backup to it, check it, unplug, check it on another computer, unplug and into safe storage. Plug it in again a couple of years later and the drive is crunchy clicking with no hope of getting it up and running again. Tried it in various other computers and still no hope. Lucky that the data was also on a backed up to a stack of DVD+RW discs, so the data was not lost to time.
The drive gets stripped down and the parts go into the scrap metal boxes.
Another dead red, red for danger as they say! All the 4tb greens I have (12 in total) made it past 60k hours and are still in use! Just bought a load more 4tb greens, might as well back a winner!
WD Red brand is a scam since its launch. Just an artificial segmentation made by locked features.
One invisible scratch that is not seen is more than enough for the servo to loose the sync with the platterns. One in one platter is enough for all to fail
Sounded like bearing failure to me, would explain the dependency on orientation for the noises. Then the motor would not reach its operating speed and the data looks garbled to the controller, hence it stops.
Could be bearings or a motor with a phase with a single shorted turn, which will mean it cannot run up to speed. Simplest test if it is a bearing is to heat it up to around 90C in the bearing area, then put the board back on and see if it starts up. The heat makes the lubricant flow again and repack the balls.
Bearings don’t fail on those. Most likely mild bad sectors / head damage that caused the drive to go offline on the array.
@@SeanBZA na man
@@SeanBZA the only drives that happened too were 20/40/60 IDE 2.5 Toshiba drives. Fix was to heat the bearings with a heat gun while imaging. You never unpack anything
*fuji
Normally for HDD warranties they don't go by the receipt / retail purchase date, but have an internal date based on the serial number, but looking this one up on their customer warranty submission page it shows expired 23-Feb-2021
Heh, another good reason to go with WD Gold / Ultrastar. 5 years of warranty :-)
That resistance you're feeling in the spindle motor is just back-EMF from the brushless motor acting on the permanent magnets in there.
Fun fact; you can connect the terminals of that motor directly to a standard hobby aircraft/drone brushless DC motor ESC to get things spinning real quick!
No PCB attached, no closed circuit, no current, no opposing force.
I believe that back EMF is in a different case of a motor, not a "generator".
@@paulcohen1555 hmm... I think you're right. Although when I spin a brushless permanent magnet motor that's disconnected, there is still a 'cogging' effect where it clicks. What causes that?
@@LazerLord10 The rotor is essentially a multi-sectioned magnet and the stator is made of sheets of laminated steel (referred to as a slotted stator). Since the stator is magnetic the rotor will "cog" to one of the positions.
Most BLDC stators are typically constructed with anywhere from 2 to 6 "pairs" and you can count them based on the number of cogging positions of the rotor.
@@LazerLord10 Simply, I don't know.
@@Derragon Similar to brushed DC motors! The worst type in the world! :D
SMR drives aren't bad per se but they definitely have preferred use cases, those being archive or sequential transfers of very large files. If you're trying to use them as a system drive in a desktop or something else with frequent random writes you're in for a bad time. Ideal use in a desktop would be combining an SSD for operating files and a large-capacity SMR drive for storage of media files that don't change much.
Platter screw was probably an ip7, torx plus #7. We used those in cell phones, they are able to take higher torque without stripping the head. Normal torx can be used, but is not the preferred tool for them. Torx plus drivers will not fit torx screws at all.
From my experience taking apart 1,000's and 1,000's of these, it's a T8. But you need really precise screwdrivers. The one I use for the platters is a T8 and it cost me about $20. Just for the one screwdriver. If you spend less money, there will always be some play and they will always strip. I found that out the hard way when I first started my computer recycling business about 12 years ago.
@@markjohnson7887 That's my experience, too. So easy to strip the head and damaged the bit at the same time if you're not careful with the trigger on the impact driver. When I line up a whole lot on the bench and get a good rhythm going, I can do about 2-3 screws a second.
@@soupisgoodfood42 I hear you there. Me too
If the other 3 drives were approaching being full and they are not in any way duplicate of each other, it is more or less impossible for a 4th "redundant" backup. This could be technically possible if the 4th was compressed and the other 3 had compressible data. If like there were 2 sets of duplicates of 2, yes. The 2 scrapes on the edge of the ring were probably balance adjustments.
Contaminations and imperfections on the disk platters might not be visible with normal light. If you care enough you can use "green light" to check for damage. See th-cam.com/video/lYHeFJf11Mo/w-d-xo.html for more information.
Dave, the so-called death clicking is not usually caused by problems on the surface of the platters. Mostly, it comes from either head assembly problems or platter motor problems. As you mentioned, tolerances are extremely small, so if heads can't move properly or platter rpm isn't spot-on, the drive's controller enters a loop trying to seek valid signal(or data - I'm not exactly sure whther it's the actual onboard controller of the HDD or the motherboard). At least that's what I remember from university :)
There is another type of click, which is more rhythmic, and very loud - that's if there's issues in the signal path of the heads so they don't get any feedback off the tracks. The servo then launches them to the middle and they hit hard and click. But that's not what you hear here.
By the way, if u listen carefully, when you spin the drive open, there is a specific sound when the heads passed over the scratch you made - that totally destroyed the head :)
Oh, one more thing - those notches on the platter shaft I think are weight balancing holes so that the center of mass is exactly in the middle.
Would have been nice to see what SMART detected if anything.
According to Dave, SMART had detected nothing. I can't recall where he said it (early) though.
@@MiniLuv-1984 He showed a screen shot in this video with all 4 drives listed and SMART saying they were OK.
@@markjohnson7887 Thank you sir! My recall de-coheres faster as the years roll on!
@@MiniLuv-1984 I haven't gotten there yet myself. But I think my time is coming soon. haha
@@markjohnson7887 Yes, unfortunately and despite the delusion of being invincible and immortal, ones reality is soon adjusted :)
The hollow traces on the head could be thermal insulation, so that the chip-on-flex does not desolder. The traces are broader than the others, so the may carry the current for writing, perhaps? What do you think?
I'm impressed that at @8:26 just after taking off the top that you've already got visible dust specks on it (upper right corner, and upper left corner near the middle of the platters). Just goes to show how important clean room facilities are due to how quickly it can become contaminated.
I have this exact same drive and it failed recently making exactly the same noise. Would appreciate if anyone can vouch for this being recoverable.
Whenever I have dead HDD that is unreadable, unformattable, and unusable, I always disassemble those, so I can get magnet inside.
should always try getting an identical used model on ebay. switch out the circuit board and you just saved your data. ..and you still have one left to tear apart :)
@@luminousfractal420 in most of my case it's a click of death
I once had an HP laptop power supply fail exactly 1 day out of warranty. Sometimes I wonder just how close these warranty periods are to the MTBF.
At first, everyone did not believe in Bitcoin, then in Defi, then in NFT, and now someone really does not believe in the RJV12 algorithm :D
Dismantled quite a few old hdd for Magnets
Made a small grinder out 1 stuck some fine sandpaper on the disk
other than that the case use for a mount etc or scrap
You should do a factory walk-through at one of the big HDD producers.
It would be amusing to see their reaction to Dave saying "don't turn it on...take it apart!"
One time I gave a friend a pair of hard drive magnets to play with - it was all fun & games until put them in his pocket. The moment they slide down inside his pocket it pinched his skin on his leg so bad it became bruised and bit bloody. Never again did he put magnets in his pocket.
and we are all paranoid about getting a magnet close to a hard drive,,, and yet the disks spin past the servo magnet cage at 5400 7200 10000 15000 rpm....
@@Okurka. as compared to stiffies?
So a trick to recover data from a failing hdd, put it is a zip lock bag remove as much air as you can (vacuum seal works too) and place in your freezer for a couple of hours. Sounds funny I know, but you would be amazed.
As for the pressurized hdd's, I think WD had a some that were "filled" with helium. Though I couldn't understand why. As helium leaks through everything, even glass.
The distance between head and platter is too small for atmospheric air molecules.
Sounds like a fully functional Seagate
I had 8 of these in a NAS, they all failed within 2 years. I used to be a loyal WD purchaser (small computer building business) but use HGST when I can't find a flash solution at a good enough price.
the sound looks more like it was the bearings failing
As a guess I think they would have a tool similar to the angle grinder tool for removing discs to remove the platter screws.
That connector looked like a grinning face. Love it!
looks like a domokon
The platters are like art. I like the idea of using them for some nouvelle art project.
That's babaric!
@@johndododoe1411 He's dead Jim!
Last 3 weeks 4 out of the 5 wd 6TB HDs failed in my nas. Had to replace all of them. All cmr versions with 30-40k hours on them. Replace 1, test, rebuild, fail another, backup all with raid in fail mode and 1hd with bad blocks. Create new raid, fail another disk after successful test. Hell of a week.
Don't jinx me...
@@EEVblog Keep testing those drives is all I can say. Not sure if my thecus is doing automatic testing. I think your Synology does.
Damn. Those hdds are really awful. Mine have over 100k hours and all 4 of them are just fine. Hdds are really going down the shitter these days.
@@EEVblog Perhaps it's time to look at using 2.5" SSDs? 8TB drives are about $1k each but live a long time..
Small update. Had to double check mine: also wd60efrx. Coincidence? Just outside warranty. 1 with clicky sound, 3 with some bad blocks.
Early IBM hdd's had replaceble heads, but the disc diameter was like 12 or 15 inches
For those who still own old, really old VHS, or especially Betamax video-recorders, yes, the precision is not as great as a modern HD, but they are a far more 'mechanically' complex device than this HD by a mile. As for precision, until the day that higher density hard-drives become the norm in homes, actually the VHS & Video-8 / Hi-8 video heads were the most accurate precision machined device consumers ever owned.
The bearings used for the head actuator and spindle motor must be built to a very high standard and tight tolerances, There's no room for any wobble or run out on a hard drive, and they have to be able to remain essentially play-free throughout their lives.