You still have a few failure points between the actual head coils and the connector. You should measure ohms *at the head* because all the bendy cable and crimped connectors between it and the pcb connector can fail, and thin cables can corrode.
I've seen the miracles you and the other members of the Centurion Squad have pulled off to get a lump of dead parts turned into two completely functional Centurion Minicomputers. I have every faith in you that you will pull this off. Never say die!
I bet the problem is the wires going to the heads are broken. Although coils can be burned by carrying too much current, it's more likely that the wires being under constant motion just broke the conductors. I would check the continuity directly at the coil-wire connection and see if it's still open circuit there. Wires are easier to replace than head transducers.
This makes me appreciate the service contract we had for our MicroVAX systems back in the day at GE. They were expensive as all getout, but the repair genie would visit and everything worked afterwards. Best of luck.
"This is the Lockpicking Computer Geek, and what I have for you today is setting a DIP switch with a wave rack... 1 is binding, 2 is a false gate, 3 is there... Okay, let's try again to see if it was not a Fluke" I was gonna suggest that you make a cutout in the upper front angle bar on that rack to clear the Hawk drive's panel, but drilling two holes was way simpler! Haha, that was just brilliant :) Got a bit worried seeing you lift the heavy thing all by yourself though. Niiiiiice platter collection there :) and good job on refurbishing the heads - pity it didn't turn out to work, but still a work of love. It can indeed get frustrating! Well... catch you next time :)
Emulate the drive, and remove the heads from the physical drive but still have it spinning with a partial head assembly still in place so you still get the kerchunka. Then split the signal so that commands get sent to both the physical drive and the virtual drive, but data is only read back from the virtual drive.
You, sir, are doing yeoman's work on these old systems. Incredible patience that you have. Good to see younger people with such a penchant for learning and problem solving. Keep up the great work, my friend.
I'll give you credit. You definitely fight through. This is very challenging especially now that parts are hard to come by. Hope you are able to get this working. I'm sure you'll be celebrating if you do. We'll be celebrating right along with you.
Before writing off those heads I would double-check to make sure there's no corrosion on the connectors, make sure crimps are solid, solder joints good, etc.
I enjoy every single frame of your videos... I've no special knowledge on old computers (I started to follow you because the use of vacuum tubes...) but let me congrats with you for the effort profused in a search for solutions of the issues you have found in your Centurion project. Great work !!!!
You just did a perfect RedGreen skit when lifting the hawk drive in. As you are going through that sequence all I am imagining is Bill trying and failing to do something, RedGreen narrating it with a tinge of disappointment, followed by success in some form. I don't know if you planned that or not, but 8:50 my favorite part of the whole video and it's only 20 seconds long.
I was servicing a big graphics workstation which had intermittent failures. I traced them to these nasty dip switches and replaced them (Approximately 15 8bit in each WS) After that I had a quiet life with no calls from the users.
I recall programming PDP 8 & 11 computers back in my student days, we sure didn’t dare take them apart back then! It’s fascinating watching you fearlessly restoring these old beauties, I’m cheering you on in the background! It’s surprising so many heads failing in the same drive, are they prone to failure or is there another cause?
I used to work on some old removable disks the video brought back some memories!! I was always careful around the heads as if we replaced one it was always a pain to get the pack alignment right. But we had only one alignment pack as they kept getting written over by mistake!!
Nice to see al the effort you put into this. It almost seems more simple to adapt a USB flash memory reader to the Hawk interface then mechanically reviving the unit
The cool thing is you can actually work on these drives. Newer spinning magnetic media drives are so tight tolerance wise, you really cannot work on them without specialized clean rooms and the like. Those drives were so expensive, that they HAD to be repairable.
It always gives me a bit of a startle to see what amounts to a hard drive platter just sitting there! Under almost any circumstances, if you can see that with a modern drive then the drive is _very_ dead.
it made me somewhat afraid of drives, that's why I use 3-way RAID redundancy and have 8 of them. they are basically irreparable and lost data is lost forever, which is why you have to use a proper RAID system that does parity and have backups, there's no recovery if they ever fail. which is basically the truth for any hard drive nowadays, they should never ever be used as a single drive for any system, unless you don't care about losing data, because you are going to eventually lose data.
The head coils are likely fine, the wires that undergo flex so that the drive can seek are probably where your problem is. I had a mouse get into a Hawk and chew the head wires (this was back in the late 70s), replacing the wires did the trick, the drive worked for years after that.
Honestly with the effort and attention to detail you've put in, and the well put together narrative you weave depending on what goes down this is more entertaining to guess and hope what happens next than Yet Another Bland Marvel Movie.
The Commodore 1541 floppy drive mechanisms made by Newtronics had a design defect where the epoxy would fail a bit and let moisture in, causing the head coils to corrode and go open. I wonder if a similar fault has happened here.
Shim the heads for the thicker disk maybe? Is the alignment tool just hard sectoring the disk for use with the controller? Old disks needed to be synchronized from what I remember Side thought, Should try bubble memory.. would be period correct I think…
Reminds me of the stuff Curious Marc does. His team tackles all kind of dinosaur computers. Not that he wouldn't touch more modern stuff on occasion. But this old stuff is intriguing. For someone growing up with C64 and following machines. (C128D, IBM PC, 486DX... Etc)
I followed every video of you rebuilding the Centurion. The effort you put into the system is remarkable, and the results are also very promising and educational. I have an HP-1000 minicomputer system with HP-7906 disk drive waiting to be restored. The disk drive is almost identical to the CDC one in your video, with one fixed and one removable 14-inch platters . I still have no courage to restore the drive because I have only one chance and if I fail, the data will be gone forever. Your detailed video have given me much more understanding about these devices than anywhere else. I really hope you can get the system repaired. Hopefully I'll also be able to power up my unit in the future.
2:48 Glad you're going to VCF East! You'll love it! May I also cordially invite you to VCFMW in Chicago in September...Let's see if we can get you a table near my Forgotten Machines display. The Centurion will fit in perfectly! I constantly have both real floppy/hard drives in real life and in emulation going on all of my systems. Most of them as rare and enigmatic as your Centurion! It will be a blast...
Good stuff. You have done amazing things with the old hardware and I love to watch your videos. No guarantee of success every time but always great to see you doing your level best. Carry on Please!
The enamelled copper wire used for the head windings might have been soldered using acid flux, which can eat through the joint. Worth checking if you can get to it
Acid flux wasn’t used in electronics back then. (It’s increasingly used today, as water-washable flux, but cannot be used in all situations.) Anyhow, are you perhaps thinking of corrosion from chemical stripping? It’s common to strip enameled magnet wire using chemical stripper, which is basically molten lye into which the wire ends are dipped. The wire is then rinsed repeatedly, including a neutralizing dip. Certainly if the rinsing was incomplete, it could cause corrosion down the line.
Strange about the heads. I'd be testing the cards carefully to make sure they're not somehow burning them out. I've not heard of that, but then I don't know anyone who's running drives that old.
Beats me but Commodore 1541 floppy drives with the Mitsumi mechanism also have head coils that fail open, I haven't found an explanation. It's also irreparable.
@@russellhltn1396 Yep that's my thoughts as well. Reminds me of the glue used on PCBs from the 80s and 90s that would turn brown and become conductive or worse corrode component legs off and wipe out traces.
@@russellhltn1396 Yes that's what makes the most sense but I don't know enough (or anything, really) about materials science and where to begin investigating. I have several dead Newtronics mechanisms to take apart the head but even if I find the cause, it's almost impossible to do anything about it, I'd say. It's awfully fine wire wound very small...
The thumbnail is SUPERB! Have you been watching Curious Marc's Alto restoration videos on endless repeat? ;) Will a Hawk drive run WITHOUT a fixed platter???
A Hawk drive shows up in the Centurion OPSYS as two logical 5MB disk drive volumes. Yes you can build up a Hawk missing one of the two platters ( fixed -or- removable ) and the heads for that missing platter can be removed. The trick is the Hawk must have sector ring pules from the fixed disk platter and the removable disk platter for the Hawk to load the heads over the remaining platter. So if you install a removable disk cart. with the platter & heads missing you still have to have the sectoring ring installed in disk cart. This is what we are now doing now, have built up a Hawk with a fixed platter & fix heads only and a cart. sector ring. Testing now under way.
Remember how you had to swap the analog board earlier in the testing to get the alignment test going? Yeeeah, that thing doesn't happen to interface with the R/W heads does it? 🤔 Sounds like both the RW and Erase heads are capable of being "driven" (signal applied to, not just read from, them). So, a control board being fried is definitely something that could knacker them, I'd suspect!
Back in the day they were a pain in the backside to fix then, and it looks like they’re going to be a pain in the backside now. Good luck!. I remember the initial seek, heads move forward at light speed “bang and break of the max distance travel stop” I was working on a newspaper “DYMO” Computer system at the time. The pressure to get it back on line was tremendous. I took them to the repair centre in Birmingham UK. What a nightmare of a unit.
Most CDC Hawk drive voice coil servo slams are caused by a failed servo feedback loop or unplugged Tach-Coil. Do agree it takes just a couple of servo slams to break the front crash stop casting.
If anyone is going to bring back this Hawk drive from the netherworld, it’s Usagi & Friends! For me as a viewer, it is at least as interesting watching all the problem solving (even if it doesn’t fit in an episode) as reaching the end goal of it working… although perhaps you could do with someone finding a box of unused CDC Hawk heads and platters!
Maybe he could get curious Marc and his crew to help. They also have experience with this kind of thing and they might also have the contacts for spare heads.
@@GrayRaceCat that has been proposed in the comments many times. Guess we will find out next video. But even if they are, can they be replaced. That depends on how they are attached to the heads, might be cast in our something.
If you have a drive head like that which has crashed badly and you find that paper isn't adequate to remove material then you can pick up some .25 micron lapping film from 3M, stick it to a sheet of float glass, and use that to lap the head. I use such film to do the final pass on knives that I'm sharpening and it leaves them with a fantastic mirror finish, so it is more than up to the task for simple hard plastics. A side benefit is that this kind of film basically never deposits its abrasive, so you can be certain that it won't leave behind any grit that might cause problems. Even when using it to sharpen knives, the only reason it stops grinding effectively is when the abrasive has clogged with metal and needs to be cleared. It's also useful to cut a small swatch and adhere it to a firm foam backing to use when trying to remove marks from paint finishes, as it is extremely fine grit and tends not to leave swirls or scratches in the paint. Just remember to wet it with water or alcohol prior to use so it won't clog the abrasive too quickly. Also, if you're curious why paper makes an acceptable abrasive: Kaolin clay. It's almost universally used in hot-press paper like printer paper to improve the color, stiffness, and surface texture of the paper. It also improves ink bonding with the paper. The fibers of the paper also function as an abrasive, but the primary abrasive is still the kaolin clay.
You should try to repair broken heads. It may be broken wires to the heads because of endless bending. Check it before panic. It may be not broken coils.
Where did you measure the resistance of the heads? At the heads them selves or from the end of the wires that go to the heads? Are the wires going to the heads possibly the part that's open circuit and you would just have to replace part of the wires? Likely the part of the wire that bends as the heads move.
In the late 70s and early 80s I was a tech that had to deal with multiple platter CDC drives that could be removed and switched for backups etc. I was just a low level tech and the whole process of switching multi platter cartridges between 2 drives for daily backups was stressful since I never knew what was going to happen when they both spun up. A whole newspaper was in the outcome. Glad those days are over. Sometimes had to run only one drive because the other was down. No fun at all and wondering if the remaining drive would survive.
I do hope for nothing but success in the end. I am crossing my fingers that much - structural finger overload warnings are constantly tickling my brain. Following your centurion adventures proved to be the "computer-thing" i am most thrilled about since the first 3dfx voodoo boards came around.
Amazing! Hope you can find some working heads. Got to admit, I'd have been inclined to build some interface to make a SSD look like a Hawk drive to the machine, and put that in the mini case. Cheating, I know.
Well, I commend you for trying to fix that drive. I have worked on similar drives early in my career and those heads are pretty durable, but maybe you should consider an alternate path. I noticed you have several CDC Wren drives, I would maybe see if you could get one of those to work. And as an added benefit it would fit in your existing case. Good Luck!
At 13:05 you show the head that didn't crash, and at 13:58 you show the crashed head. Not sure if it's just an optical illusion or what, but it looks like the end of the head further from the two holes is sitting lower in the whatever the brown material is than the uncrashed head. It's like the brown material heated up and the head moved in it.
how to make head. measure ferrite permeability, cut head cross section and count turns, file down ferrite core, wound thin enameled wire, encapsulate in epoxy
Hi, I was wondering if you considered that the cabling leading up to the coil may have internally decapitated. Considering how much back and forth the head goes they may have worn out and snapped. Hope this little observation helps. 🤠
That was probably me that bought the head, haha. Unfortunately, it's the incorrect type, the erase head on it has about 15x as much resistance as the ones that this drive uses. Most likely a straddle erase head vs. a pre-erase head. If I had a lower and an upper straddle erase, I could set the drive up to use them, but the Centurion software would probably not work due to timing problems. If you come across any more though, let me know!
@@UsagiElectric I have also been working on building a CDC Hawk drive. Only difference is that I am starting out with no drive and building it from parts off of ebay. My goal is to make it work then create a USB interface for it with Windows. It is part of my project of combining old and new tech.
Thank you for the great video! I believe in you. You have hacked your way out of so many other hard problems, I think you will hack your way out of this one.
You'd typically use an SD card, because the QSPI interface is a lot more microcontroller-friendly, and then communicate with the rest of the computer via GPIOs. Basically like BlueSCSI does it.
Great stuff. I hope to see you at VCF (if I can make it this year.) Any chance of doing a virtual drive (you know .. use a flux capacitor and a few muffler bearings to make an interface that looks just like the drive, but accesses an SD card?)
This is a shot in the dark but have you checked any capacitors on any of the hardware going to the heads, maybe voltage spikes have happened blowing those coils open. I’ll admit I have no idea about any of this hardware. But if something was sending current in the wrong direction I would imagine that wire might pop like a fuse
It seems like you have been measuring the coils at the connector, rather than the coils themselves. I wouldn't get my hopes up, but there is a very slight chance it's not the coils but the cable that's broken. After all, it's been bending back and forth with every seek for who knows how long. Maybe try piercing through the cable insulation with a needle as close to the coils as you can get and measure there?
Not that I'm suggesting this as an alternative to fixing the Hawk, but wonder if it would be possible to make a storage solution with a modern SSD that 'looks' like a Hawk drive to the Centurion? Might be useful for day-to-day use so as not to put wear on the original drives.
As much as I appreciate the real thing, for a mobile demonstration system I'd go with an emulated drive. The real Hawk is too big and fragile to be hauling around. -- Looking forward to seeing this at VCF East!
Bummer.. coils can burn out in that older stuff (make sure there isnt a fault in any of the logic cards causing them to burn out!) have you verified the coils are actually dead and there isnt a break in the long wiring from the heads, there is quite a bit of flex in the cable and it could cause a break over the years.
An absolutely excellent quote, anyone with the interest to do so can achieve stuff like this if they want it, you don't need to be a genius, building and fixing things has never been a insurmountable challenge unless a company deliberately spends lots of effort to make it as difficult as possible, ie Apple
Please, if you haven’t already, consider putting your own spin on the recently released new old stock “Nabu” computers that were discovered from the 1980s, and that are now being sold brand new for dirt cheap. I’m about to get my own, but will need guidance on what to do with it. There are some AMAZING things being done with it already, e.g. the “ElectroGeek64” channel, but I would be fascinated to see what you can do with an original, yet brand new, 8 bit computer from the 1980s…
People nowadays are spoiled with their fast and reliable hard drives. They need to know the pain of using floppies for everything. Maybe someone can set up a way to load things over a serial connection. If the Centurion's serial ports are fast enough, it could be a viable alternative.
I've see you and yours in action -- you will figure this out. Here's a question: could an ST-506 drive be adapted to serve in time for the meets you need to make, or is this interface (SMD) more akin to SCSI. Could another Finch drive be made to serve? (I know... the ST-506 thing is akin to heresy, but it would beat a dead and non-working machine.) However you decide to proceed, I'm sure you will eventually prevail. Ganbatte, yo!
It seems unlikely that those heads all failed open in the exact same way. Can you rule out the small cables between the connectors and the heads themselves? You can pierce through the insulation with a small strait pin.
For a VCF - no time this time - I would look for one of those PC designs (were all 200 shown to IBM working / IBMs Rebadged with just one or to to the EDS/ Centurion Division full internal spec ?) They seem as if they could be to the Centurion Systems like the DEC Rainbow was to the DECs as a terminal/local desktop computer , with scope to run a number of programms
The EDS-Centurion PC was 100% a clone of the IBM PC of the day (with a few EDS value add features). The EDS-Centurion PC was built as a XT model. At one time we had a large number of Intel 286 CPU chips on order to start building the EDS-Centurion AT class PC the IBM came around to the price point EDS would pay and EDS shutdown the EDS-Centurion PC project.
@@kenromaine2387 I would have thought that having Centurion as a brand for a PC would have matched the brand at least to Compaq (with the extra features of being a little ahead of IBM), selling into the market EDS already had rather than yielding to IBM (Though the 286 was my favourite intel variant - I had a UK assembled clone from a local builder (I had a 8086 too , cannot remember the make , which was too bulky ) We had AN Olivetti 8086 lovely design but so slow plus A Compaq ( our budgets- and space, were small ), everything else ran on a DEC PDP. I upgraded my 286 to a 386SX which was good enough for lotus 123 and a couple of graph and accounting programs plus wordstar (later word perfect). I was also an end user of a Thorn-EMI system that ran custom software but was very fast for 1986. I suppose really the PC eventually won in the commercial marketplace because of the availability of lots of commercial software, but it always seemed odd we went and got standalone processing boxes then a few years later wanted to network them all together.
The head allignment problem might be caused by the servo control loop. If it is controlled by an analog circuit, the component values may drift in time. Just an opinion, I don't know how these hard drives work in detail.
wow 3 head showing open circuit is bat enough! Might be a faulty head amplifier feeding excessive voltage to the heads thus sending the coils to the 9th dimension ?
Wow. If the cores are still good, you might be able to rewind them. Or maybe they have a bad connection point somewhere. Long ago when I was crippled poor, I rewound the head on a 1.44 floppy drive. Just be sure to count the turns taking the old wire off.
You still have a few failure points between the actual head coils and the connector. You should measure ohms *at the head* because all the bendy cable and crimped connectors between it and the pcb connector can fail, and thin cables can corrode.
YES! I was hoping someone thought of this!
very likely this is the issue
I've seen the miracles you and the other members of the Centurion Squad have pulled off to get a lump of dead parts turned into two completely functional Centurion Minicomputers. I have every faith in you that you will pull this off. Never say die!
I bet the problem is the wires going to the heads are broken. Although coils can be burned by carrying too much current, it's more likely that the wires being under constant motion just broke the conductors. I would check the continuity directly at the coil-wire connection and see if it's still open circuit there. Wires are easier to replace than head transducers.
I was thinking the same thing!
@@Derundurel so was i, guess we'll know in the next episode.
This makes me appreciate the service contract we had for our MicroVAX systems back in the day at GE. They were expensive as all getout, but the repair genie would visit and everything worked afterwards. Best of luck.
"This is the Lockpicking Computer Geek, and what I have for you today is setting a DIP switch with a wave rack... 1 is binding, 2 is a false gate, 3 is there... Okay, let's try again to see if it was not a Fluke"
I was gonna suggest that you make a cutout in the upper front angle bar on that rack to clear the Hawk drive's panel, but drilling two holes was way simpler! Haha, that was just brilliant :)
Got a bit worried seeing you lift the heavy thing all by yourself though.
Niiiiiice platter collection there :) and good job on refurbishing the heads - pity it didn't turn out to work, but still a work of love. It can indeed get frustrating! Well... catch you next time :)
Awesome comment!
Emulate the drive, and remove the heads from the physical drive but still have it spinning with a partial head assembly still in place so you still get the kerchunka. Then split the signal so that commands get sent to both the physical drive and the virtual drive, but data is only read back from the virtual drive.
Which defeats the purpose completly.
You, sir, are doing yeoman's work on these old systems. Incredible patience that you have. Good to see younger people with such a penchant for learning and problem solving. Keep up the great work, my friend.
I'll give you credit. You definitely fight through. This is very challenging especially now that parts are hard to come by. Hope you are able to get this working. I'm sure you'll be celebrating if you do. We'll be celebrating right along with you.
Before writing off those heads I would double-check to make sure there's no corrosion on the connectors, make sure crimps are solid, solder joints good, etc.
Those heads look so happy to be cleaned.
I enjoy every single frame of your videos... I've no special knowledge on old computers (I started to follow you because the use of vacuum tubes...) but let me congrats with you for the effort profused in a search for solutions of the issues you have found in your Centurion project. Great work !!!!
You just did a perfect RedGreen skit when lifting the hawk drive in. As you are going through that sequence all I am imagining is Bill trying and failing to do something, RedGreen narrating it with a tinge of disappointment, followed by success in some form. I don't know if you planned that or not, but 8:50 my favorite part of the whole video and it's only 20 seconds long.
You'll get there, Nakazoto! Remember: You're destined to take SkyNet down 😂
sudo shred-fuz /usr/bin/skynet; sudo rm -rf /etc/skynet
There is no fate but what we make ;-)
I would never have thought of dip switches causing issues. I learned something new from you today.
I was servicing a big graphics workstation which had intermittent failures.
I traced them to these nasty dip switches and replaced them (Approximately 15 8bit in each WS)
After that I had a quiet life with no calls from the users.
I recall programming PDP 8 & 11 computers back in my student days, we sure didn’t dare take them apart back then! It’s fascinating watching you fearlessly restoring these old beauties, I’m cheering you on in the background! It’s surprising so many heads failing in the same drive, are they prone to failure or is there another cause?
Glad I got to see the mini centurion but I think your plans make a lot of sense! Nice work!
Was awesome to see it in person. Was a well done build!
I used to work on some old removable disks the video brought back some memories!! I was always careful around the heads as if we replaced one it was always a pain to get the pack alignment right. But we had only one alignment pack as they kept getting written over by mistake!!
Rule one turn ON the write protect switch anytime when using the CE Alignment Pack & rule two check rule one.
Nice to see al the effort you put into this. It almost seems more simple to adapt a USB flash memory reader to the Hawk interface then mechanically reviving the unit
excellent video! good luck with the drive!
1:30 WIPL stands for Warrex Initial Program Loader. There's more info in the Centurion wiki, which is googleable. You're welcome, new viewers.
Fantastic effort trying to get the drive working! I’m sure you’ll get it up and running. Your tenacity and imagination will succeed in the end.
The cool thing is you can actually work on these drives. Newer spinning magnetic media drives are so tight tolerance wise, you really cannot work on them without specialized clean rooms and the like. Those drives were so expensive, that they HAD to be repairable.
It always gives me a bit of a startle to see what amounts to a hard drive platter just sitting there! Under almost any circumstances, if you can see that with a modern drive then the drive is _very_ dead.
my new 14TB drive is so tight tolerance that it uses helium instead of air (so the heads can float even closer I guess), its totally sealed
it made me somewhat afraid of drives, that's why I use 3-way RAID redundancy and have 8 of them. they are basically irreparable and lost data is lost forever, which is why you have to use a proper RAID system that does parity and have backups, there's no recovery if they ever fail.
which is basically the truth for any hard drive nowadays, they should never ever be used as a single drive for any system, unless you don't care about losing data, because you are going to eventually lose data.
@@monad_tcp Which RAID do you prefer? I'm not educated on the differences, and have never been able to figure it out for myself.
The low density and error checking of those makes a clean room superfluous.
The head coils are likely fine, the wires that undergo flex so that the drive can seek are probably where your problem is. I had a mouse get into a Hawk and chew the head wires (this was back in the late 70s), replacing the wires did the trick, the drive worked for years after that.
Honestly with the effort and attention to detail you've put in, and the well put together narrative you weave depending on what goes down this is more entertaining to guess and hope what happens next than Yet Another Bland Marvel Movie.
Send it curious marc that mans channel is a wizard with crashed heads
The Commodore 1541 floppy drive mechanisms made by Newtronics had a design defect where the epoxy would fail a bit and let moisture in, causing the head coils to corrode and go open. I wonder if a similar fault has happened here.
More power to ya brutha! 🤞
Shim the heads for the thicker disk maybe?
Is the alignment tool just hard sectoring the disk for use with the controller? Old disks needed to be synchronized from what I remember
Side thought, Should try bubble memory.. would be period correct I think…
Reminds me of the stuff Curious Marc does. His team tackles all kind of dinosaur computers. Not that he wouldn't touch more modern stuff on occasion. But this old stuff is intriguing. For someone growing up with C64 and following machines. (C128D, IBM PC, 486DX... Etc)
I followed every video of you rebuilding the Centurion. The effort you put into the system is remarkable, and the results are also very promising and educational. I have an HP-1000 minicomputer system with HP-7906 disk drive waiting to be restored. The disk drive is almost identical to the CDC one in your video, with one fixed and one removable 14-inch platters . I still have no courage to restore the drive because I have only one chance and if I fail, the data will be gone forever. Your detailed video have given me much more understanding about these devices than anywhere else. I really hope you can get the system repaired. Hopefully I'll also be able to power up my unit in the future.
Glad you are attenting VCF East! Can't wait to see what you bring with you!
I love how the camera angles make the lower head look happy and the upper head look dismayed.
Edit: OMG your bunny looks so happy at the end!
2:48 Glad you're going to VCF East! You'll love it! May I also cordially invite you to VCFMW in Chicago in September...Let's see if we can get you a table near my Forgotten Machines display. The Centurion will fit in perfectly! I constantly have both real floppy/hard drives in real life and in emulation going on all of my systems. Most of them as rare and enigmatic as your Centurion! It will be a blast...
Good stuff. You have done amazing things with the old hardware and I love to watch your videos. No guarantee of success every time but always great to see you doing your level best. Carry on Please!
I have the utmost faith you will get this working.
The enamelled copper wire used for the head windings might have been soldered using acid flux, which can eat through the joint. Worth checking if you can get to it
Acid flux wasn’t used in electronics back then. (It’s increasingly used today, as water-washable flux, but cannot be used in all situations.) Anyhow, are you perhaps thinking of corrosion from chemical stripping? It’s common to strip enameled magnet wire using chemical stripper, which is basically molten lye into which the wire ends are dipped. The wire is then rinsed repeatedly, including a neutralizing dip. Certainly if the rinsing was incomplete, it could cause corrosion down the line.
Strange about the heads. I'd be testing the cards carefully to make sure they're not somehow burning them out. I've not heard of that, but then I don't know anyone who's running drives that old.
Beats me but Commodore 1541 floppy drives with the Mitsumi mechanism also have head coils that fail open, I haven't found an explanation. It's also irreparable.
@@8BitNaptime If it's not being burned open, then likely some material used is corrosive over time and eating the wire open.
@@russellhltn1396 Yep that's my thoughts as well. Reminds me of the glue used on PCBs from the 80s and 90s that would turn brown and become conductive or worse corrode component legs off and wipe out traces.
@@russellhltn1396 Yes that's what makes the most sense but I don't know enough (or anything, really) about materials science and where to begin investigating. I have several dead Newtronics mechanisms to take apart the head but even if I find the cause, it's almost impossible to do anything about it, I'd say. It's awfully fine wire wound very small...
That's a really tough break. I hope you manage to salvage some heads from who-knows-where... Must be some out there. Good luck!
One thing to test is the wires between the head and the connector. The coils may be fine but the wires can be broken.
Very nice work indeed, I just still can't believe you are taking the hawk on a road trip :D -Looking amazing, wish I could assist more :)
I am pleased it didn't work first time. This is what makes your videos so exciting to watch.
Good luck! You will get there. I really like your videos and style.
You Sir, are a Legend!
The thumbnail is SUPERB!
Have you been watching Curious Marc's Alto restoration videos on endless repeat? ;)
Will a Hawk drive run WITHOUT a fixed platter???
A Hawk drive shows up in the Centurion OPSYS as two logical 5MB disk drive volumes. Yes you can build up a Hawk missing one of the two platters ( fixed -or- removable ) and the heads for that missing platter can be removed. The trick is the Hawk must have sector ring pules from the fixed disk platter and the removable disk platter for the Hawk to load the heads over the remaining platter. So if you install a removable disk cart. with the platter & heads missing you still have to have the sectoring ring installed in disk cart. This is what we are now doing now, have built up a Hawk with a fixed platter & fix heads only and a cart. sector ring. Testing now under way.
Remember how you had to swap the analog board earlier in the testing to get the alignment test going? Yeeeah, that thing doesn't happen to interface with the R/W heads does it? 🤔
Sounds like both the RW and Erase heads are capable of being "driven" (signal applied to, not just read from, them). So, a control board being fried is definitely something that could knacker them, I'd suspect!
Yes the only way they would be open is too much current or badly corroded enough to break the copper wires.
I wonder if the bad analog board played any part in the heads going open circuit?
That was the first thing I thought of to.
Back in the day they were a pain in the backside to fix then, and it looks like they’re going to be a pain in the backside now. Good luck!. I remember the initial seek, heads move forward at light speed “bang and break of the max distance travel stop” I was working on a newspaper “DYMO” Computer system at the time. The pressure to get it back on line was tremendous. I took them to the repair centre in Birmingham UK. What a nightmare of a unit.
Most CDC Hawk drive voice coil servo slams are caused by a failed servo feedback loop or unplugged Tach-Coil. Do agree it takes just a couple of servo slams to break the front crash stop casting.
If anyone is going to bring back this Hawk drive from the netherworld, it’s Usagi & Friends! For me as a viewer, it is at least as interesting watching all the problem solving (even if it doesn’t fit in an episode) as reaching the end goal of it working… although perhaps you could do with someone finding a box of unused CDC Hawk heads and platters!
Maybe he could get curious Marc and his crew to help. They also have experience with this kind of thing and they might also have the contacts for spare heads.
Is it posible that the leads between the heads and the connectors have failed?
@@GrayRaceCat that has been proposed in the comments many times. Guess we will find out next video. But even if they are, can they be replaced. That depends on how they are attached to the heads, might be cast in our something.
Is it definitely the coils that are bad, and not the wires to the coils? It lookslike those flex a lot in service.
Wow... this is worth checking out. It may save you some real headaches and expense.
If you have a drive head like that which has crashed badly and you find that paper isn't adequate to remove material then you can pick up some .25 micron lapping film from 3M, stick it to a sheet of float glass, and use that to lap the head. I use such film to do the final pass on knives that I'm sharpening and it leaves them with a fantastic mirror finish, so it is more than up to the task for simple hard plastics. A side benefit is that this kind of film basically never deposits its abrasive, so you can be certain that it won't leave behind any grit that might cause problems. Even when using it to sharpen knives, the only reason it stops grinding effectively is when the abrasive has clogged with metal and needs to be cleared. It's also useful to cut a small swatch and adhere it to a firm foam backing to use when trying to remove marks from paint finishes, as it is extremely fine grit and tends not to leave swirls or scratches in the paint. Just remember to wet it with water or alcohol prior to use so it won't clog the abrasive too quickly.
Also, if you're curious why paper makes an acceptable abrasive: Kaolin clay. It's almost universally used in hot-press paper like printer paper to improve the color, stiffness, and surface texture of the paper. It also improves ink bonding with the paper. The fibers of the paper also function as an abrasive, but the primary abrasive is still the kaolin clay.
You should try to repair broken heads. It may be broken wires to the heads because of endless bending. Check it before panic. It may be not broken coils.
Where did you measure the resistance of the heads? At the heads them selves or from the end of the wires that go to the heads? Are the wires going to the heads possibly the part that's open circuit and you would just have to replace part of the wires? Likely the part of the wire that bends as the heads move.
make or get a couple of countersunk bolts for the wheels
In the late 70s and early 80s I was a tech that had to deal with multiple platter CDC drives that could be removed and switched for backups etc. I was just a low level tech and the whole process of switching multi platter cartridges between 2 drives for daily backups was stressful since I never knew what was going to happen when they both spun up. A whole newspaper was in the outcome. Glad those days are over. Sometimes had to run only one drive because the other was down. No fun at all and wondering if the remaining drive would survive.
I do hope for nothing but success in the end. I am crossing my fingers that much - structural finger overload warnings are constantly tickling my brain. Following your centurion adventures proved to be the "computer-thing" i am most thrilled about since the first 3dfx voodoo boards came around.
wonderful video
I live about 30 miles away from vcf east and look forward to seeing this "beast" in person.
Amazing! Hope you can find some working heads. Got to admit, I'd have been inclined to build some interface to make a SSD look like a Hawk drive to the machine, and put that in the mini case. Cheating, I know.
Well, I commend you for trying to fix that drive. I have worked on similar drives early in my career and those heads are pretty durable, but maybe you should consider an alternate path. I noticed you have several CDC Wren drives, I would maybe see if you could get one of those to work. And as an added benefit it would fit in your existing case. Good Luck!
At 13:05 you show the head that didn't crash, and at 13:58 you show the crashed head. Not sure if it's just an optical illusion or what, but it looks like the end of the head further from the two holes is sitting lower in the whatever the brown material is than the uncrashed head. It's like the brown material heated up and the head moved in it.
The heads look so happy :)
how to make head. measure ferrite permeability, cut head cross section and count turns, file down ferrite core, wound thin enameled wire, encapsulate in epoxy
Hi,
I was wondering if you considered that the cabling leading up to the coil may have internally decapitated. Considering how much back and forth the head goes they may have worn out and snapped.
Hope this little observation helps. 🤠
Are you sure you don't have some open diodes? I know they usually fail shorted, but I have had a bunch fail open.
You have so many brilliant contributors, maybe someone can come up with an interface for a modern mass storage device?
Just checked my eBay watch list and unfortunately someone bought the CDC Hawk heads I was looking at. I will keep an eye out for another set.
That was probably me that bought the head, haha.
Unfortunately, it's the incorrect type, the erase head on it has about 15x as much resistance as the ones that this drive uses. Most likely a straddle erase head vs. a pre-erase head. If I had a lower and an upper straddle erase, I could set the drive up to use them, but the Centurion software would probably not work due to timing problems.
If you come across any more though, let me know!
@@UsagiElectric If possible I would buy those incorrect heads off of you.
@@UsagiElectric I have also been working on building a CDC Hawk drive. Only difference is that I am starting out with no drive and building it from parts off of ebay.
My goal is to make it work then create a USB interface for it with Windows. It is part of my project of combining old and new tech.
Good job my friend
Thank you for the great video!
I believe in you. You have hacked your way out of so many other hard problems, I think you will hack your way out of this one.
Great job, it's real ballsy to attempt to use that platter, but it's the only way. I believe in you!
13:51 the head looks freaking excited!
Hawk heads looks like a happy face.
How hard would it be to replace those drivers with some sort of CF card device that mimics the drive? I’m sure it would take a lot of work.
I was just gonna say that ^^^
You'd typically use an SD card, because the QSPI interface is a lot more microcontroller-friendly, and then communicate with the rest of the computer via GPIOs. Basically like BlueSCSI does it.
Great stuff. I hope to see you at VCF (if I can make it this year.) Any chance of doing a virtual drive (you know .. use a flux capacitor and a few muffler bearings to make an interface that looks just like the drive, but accesses an SD card?)
This is a shot in the dark but have you checked any capacitors on any of the hardware going to the heads, maybe voltage spikes have happened blowing those coils open. I’ll admit I have no idea about any of this hardware. But if something was sending current in the wrong direction I would imagine that wire might pop like a fuse
It seems like you have been measuring the coils at the connector, rather than the coils themselves. I wouldn't get my hopes up, but there is a very slight chance it's not the coils but the cable that's broken. After all, it's been bending back and forth with every seek for who knows how long. Maybe try piercing through the cable insulation with a needle as close to the coils as you can get and measure there?
See you at VCF!
Not that I'm suggesting this as an alternative to fixing the Hawk, but wonder if it would be possible to make a storage solution with a modern SSD that 'looks' like a Hawk drive to the Centurion? Might be useful for day-to-day use so as not to put wear on the original drives.
As much as I appreciate the real thing, for a mobile demonstration system I'd go with an emulated drive. The real Hawk is too big and fragile to be hauling around. -- Looking forward to seeing this at VCF East!
You've come so far.
That crashed platter would make for one hell of a wall ornament
I just love the fact that the head look like little cute faces.
Startech products seem to be very well built and sturdy. I’ve been using their gear for probably about 20 years.
This video was featured on Hackaday, and some folks there might have tools to align the drives, so please have a look.
Bummer.. coils can burn out in that older stuff (make sure there isnt a fault in any of the logic cards causing them to burn out!) have you verified the coils are actually dead and there isnt a break in the long wiring from the heads, there is quite a bit of flex in the cable and it could cause a break over the years.
23:30 you wont have to worry about microamps that meter injects, when dem heads uses milliamps of current
That head looked sad before cleanup and then after cleaning it looks happy :D
Oh, good… I was thinking about one of those racks for my 68010/Z80 project. 🤔
Sometimes extraordinary things happen when ordinary people refuse to quit.
An absolutely excellent quote, anyone with the interest to do so can achieve stuff like this if they want it, you don't need to be a genius, building and fixing things has never been a insurmountable challenge unless a company deliberately spends lots of effort to make it as difficult as possible, ie Apple
Please, if you haven’t already, consider putting your own spin on the recently released new old stock “Nabu” computers that were discovered from the 1980s, and that are now being sold brand new for dirt cheap. I’m about to get my own, but will need guidance on what to do with it. There are some AMAZING things being done with it already, e.g. the “ElectroGeek64” channel, but I would be fascinated to see what you can do with an original, yet brand new, 8 bit computer from the 1980s…
People nowadays are spoiled with their fast and reliable hard drives. They need to know the pain of using floppies for everything.
Maybe someone can set up a way to load things over a serial connection. If the Centurion's serial ports are fast enough, it could be a viable alternative.
I hope I am not the only one that sees a smiley face on the hard drive heads.
I've see you and yours in action -- you will figure this out. Here's a question: could an ST-506 drive be adapted to serve in time for the meets you need to make, or is this interface (SMD) more akin to SCSI. Could another Finch drive be made to serve? (I know... the ST-506 thing is akin to heresy, but it would beat a dead and non-working machine.)
However you decide to proceed, I'm sure you will eventually prevail. Ganbatte, yo!
It seems unlikely that those heads all failed open in the exact same way. Can you rule out the small cables between the connectors and the heads themselves? You can pierce through the insulation with a small strait pin.
For a VCF - no time this time - I would look for one of those PC designs (were all 200 shown to IBM working / IBMs Rebadged with just one or to to the EDS/ Centurion Division full internal spec ?) They seem as if they could be to the Centurion Systems like the DEC Rainbow was to the DECs as a terminal/local desktop computer , with scope to run a number of programms
The EDS-Centurion PC was 100% a clone of the IBM PC of the day (with a few EDS value add features). The EDS-Centurion PC was built as a XT model. At one time we had a large number of Intel 286 CPU chips on order to start building the EDS-Centurion AT class PC the IBM came around to the price point EDS would pay and EDS shutdown the EDS-Centurion PC project.
@@kenromaine2387 I would have thought that having Centurion as a brand for a PC would have matched the brand at least to Compaq (with the extra features of being a little ahead of IBM), selling into the market EDS already had rather than yielding to IBM (Though the 286 was my favourite intel variant - I had a UK assembled clone from a local builder (I had a 8086 too , cannot remember the make , which was too bulky ) We had AN Olivetti 8086 lovely design but so slow plus A Compaq ( our budgets- and space, were small ), everything else ran on a DEC PDP. I upgraded my 286 to a 386SX which was good enough for lotus 123 and a couple of graph and accounting programs plus wordstar (later word perfect). I was also an end user of a Thorn-EMI system that ran custom software but was very fast for 1986. I suppose really the PC eventually won in the commercial marketplace because of the availability of lots of commercial software, but it always seemed odd we went and got standalone processing boxes then a few years later wanted to network them all together.
The head allignment problem might be caused by the servo control loop. If it is controlled by an analog circuit, the component values may drift in time. Just an opinion, I don't know how these hard drives work in detail.
Wondering how costly is it to manufacture new platters/heads. We have had decades of technological progress since.
wow 3 head showing open circuit is bat enough! Might be a faulty head amplifier feeding excessive voltage to the heads thus sending the coils to the 9th dimension ?
Bunny is having a lot of fun, even if you aren't!
Wow. If the cores are still good, you might be able to rewind them. Or maybe they have a bad connection point somewhere. Long ago when I was crippled poor, I rewound the head on a 1.44 floppy drive. Just be sure to count the turns taking the old wire off.