HP with a kinda-shorted power rail - LFC
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- เผยแพร่เมื่อ 27 พ.ค. 2024
- This one bamboozled me. Was it bad probing? Was it a weird partial-short? I'm not sure. Video is long because learning how to look at a board you've never seen and start understanding it is important.
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For the eagle-eyed viewers, yes I did snap the speaker plug just before I took off the top case. I fixed it, but the section got cut because it would've made the video another 10mins longer for a problem easily solved with a £5 part on ebay 😛
So blessed to have this is just Great, 38 min has passed and I felt like it was 3 min, I'm quite sure another 10 min wouldn't be in anyway an issue honestly
Graham, I tend to agree with most of the other viewers here. These videos are incredibly therapeutic and educational. You are human and will make mistakes. If people cannot let that go, that's just sad. Back in the real world, those of use who have been around a spell understand that things like this happen and you can be forgiven because you fixed it anyhow. I'm just glad that you post these videos and that you show everyone here on TH-cam how a business-owning computer technician fixes things in the real world, having to take into account real world prices, shrinking profit margins, and customers and TH-cam commenters that may miss the greater value offered by your shop. Thank you for your great videos!
@@sugargliderdude Yes, it was shown in the video.
@@sugargliderdude yes. it s in the video at 34:43
Excuse me, I have a question about the ENE controller, Does it came ready to use? or you have to program it to run properly on board?
I personally find these videos very therapeutic and relaxing …. In addition to problem solving 👍🤩
I thought I was the only one with the same experience.
Same
Probes - good or bad, simply touch the probes together and see what the meter reads. Take that into account when you go probing the boards.
I was struggling to find some fine tip multimeter probes. I ended up just simply soldering dress making pins to the tips of my probes, its crude but is a total game changer, especially on newer laptops where components are getting increasingly smaller. also if you snap a probe its really cheap to replace the tip.
Great, you're one that actually investigate and find out whats problem.. comparing to other repair shop they just ahh its a dead without actually find out and still charge you money. Good we have you.
Cap can partial-short and fully short that you can easily push 6Amps without heating much, Good practice to see if you have an high side short is to measure from the main power rail to all the coils if there is no short you can safely inject voltage. 👍
Love to watch you fix things. Has given me confidence to repair my older equipment. Just repasted the CPU and GPU on an old Dell latitude laptop (lap burner) and got nealy 15 deg C improvement.
Excellent video as always! Thank you for taking the time to explain even the small details other people gloss over. Makes a huge difference for hobbyists like myself!
Cheers, I try to mention the things that I struggled with when I was watching other people's videos to learn, so while these videos aren't unique, they might at least have the missing titbits that someone's trying to understand.
Hey Graham, another excellent video with thorough explanation as you go along. I think the meter probes you have currently are good enough, however, I can recommend getting a negative lead with a crocodile clip, then you can just attach it to a ground plane and pretty much forget about it while probing with the positive lead.
I've seen some folks do that, but it's less helpful when you need to check paths with continuity, or check directly across a component.
Your videos are absolutely the best diy electronic videos on youtube. Love em.
Thanks for all the great content. Computers have been a passion of mine since the Apple IIe. Have been inspired by content creators such as yourself to pursue my passion and started an IT career for myself. Continue doing what you do and inspire others to follow their passions.
I always forget to check for parts on my workspace, I once forgot to connect a WiFi antenna to a laptop and spent 3 hours scratching my head as to why I couldn't get the stupid wifi working
Early 1980's electronic forecourt fuel pumps i worked on which blow a fuse ,used to put a bigger fuse in and watch to see what got hot or smoked ,then changed that .'voltage injection' the components were big and easy to spot.
Mate.... you are a modern day Spock. Your knowledge of circuit boards astounds me.
Nice repair once again! Thanks for the educational content! very helpful
Fantastic work as usual! The best way to learn is through practice and lost of examples. I agree with what you said. Not every situation is the same and what applies to one repair does not necessarily apply to another. Keep up the great content! Thank you 😊
It was the first time that i could hear some music in the background. The repair it self was quit dificult to me. I had to wach the whole video twice. But thank you for teaching this to us.
Thank you for another great tutorial and the effort you take to explain the details. The simplest things for beginners helps build confidence in attempting repairs.
Hard to believe all that was only one Cap. I enjoy the way you lead the diagnosis and how you come about the repair, Thank you for another good lesson on how to do my job better.
Good Job.
Thanks for the knowledge.
Hello from Greece.
Steps nicely explained. Thanks!
34:28 I sooooo appreciate the many examples you have the channel.
Very informative video and a great piece of troubleshooting.
Am learning heaps. Was seriously about to do an injection based on 8ohm main rail before I watched your videos.
Interesting detective work. Thanks.
excellent video
Nice repair. Well done.
Loved the video Graham You're a natural teacher.
When it comes to laptop repairs, i'm glad they really don't build them like this anymore! So many screws and have to take the whole damn thing apart
Moral of the story - another great repair video!
Beautiful fix as always 👍
Thank you very much for sharing. It was difficult for me to write a summary of what was seen here but I saved it in my favorites. Indeed download the user manual of your DMM and it does not have the "REL" function. An affectionate greeting.
Nice work, thank you.
You are great makes much fun to watch your vids.
I always learn something new from you!
I have probes of the price of a few USD and the resistance is super low, about 0,1 ohm. I think it was shipped alongside a cheap musttool multimeter (MT108T). By the way thank you for the videos. I really like the way you're teaching and telling very very important details.
So blessed to have this is just Great 38 min and I felt like it was 3 min, confusing really
great video!
Good video, well done!
If you go for new multimeter probes, note that the Aneng uses short shrouds. I tried mine with some Fluke probes (I haven't got a Fluke multimeter, I got the probes to replace the Aneng ones before realising the shroud length problem...) and the fit was a bit loose, but some Brymen probes (I have a BM-257S and it is decent) fitted sort-of OK. I suspect you could shorten the safety shrouds, especially if you aren't going to use them for anything higher voltage than what's found in a laptop.
I liked the message at the end about upcycling. I have an old i3 Fujitsu laptop, doubled the ram, ssd and most importantly Linux Mint and it has never been faster! Way less than £100.
Look at you getting all these comments and subs!! Good stuff mate! Keep them coming.
With those older laptops you can also buy a caddy to replace the CD drive with the HDD for expanded storage. That's what I did with my old Toshiba L655 when I upgraded it to an i5.
Yeah, old laptops are great except the iGPU sucks, they don't have modern video decoding, meaning it has to do software decoding and spikes upwards of 50% or more CPU usage just to do basic youtube streaming, otherwise they make awesome NAS/homelab servers.
I’d rather have the optical drive.
@@vgamesx1 the iGPU in this should have video deciding. Maybe not for 4K or anything, but 1080p should do fine.
Thank you
thanks Graham
I have Pomona measurements leads. Worth of 40-50e, spring loaded sharp golden tips and small wire. very nice for probing SMD packages etc and make good contact.
I just need a playlist of people tracking down shorts, could watch forever
Gran trabajo de investugacion entre otros y gran leccion de electronica y busqueda del fallo.
Nice work
Thanks!
Thanks again.
Another interesting video. 👍👍
Thank you, awesome video as always. I was wondering what brand and model of microscope you are using. Thanks 👍
The probes with my Brymen BM867s have 0.2 Ohms of resistance. So yes you can do significantly better then 0.5 Ohms. But at the same time, it's a predictable offset value, so it doesn't matter that much.
I've got two older Envy 17 inch laptops that have very similar issues lol. One had liquid damage but still turned on, the other was working 100% then just flat out died. They both now have the same no power issue, but the liquid damaged one shows the HP logo then shuts off sometimes. That one also doesn't detect batteries, or SATA interfaces, but PCIe works and it will charge and run off the battery. I've been interested in getting these guys fixed, the GT 750M in them is still a pretty alright dGPU for what I do lol
Hi Graham - just use the “Rel” button on your multimeter to zero out your lead resistance. Looks to be the top right yellow button.
Good probes are better but of course none are zero resistance. They usually are much more flexible owing to being made of many many fine wires and softer insulation.
Ah, I've seen Rel on other meters, but I don't think the AN8008 has it... the top-right button is mode select (resistance, cont, diode, etc) or Hold. Good tip that other people might be able to use though!
Another great video. Can you please explain what is different between ohm and diode reading. Lot of people's checking in diode mode. I lost my self. 😊 🙏 thx once again sharing you knowledge with us.
I had the same problem with meter probes. The ends were crimped instead of soldered. They're soldered now...
dead handy those thermal cameras...👍😃
Hi Adam! Love your videos! Would a power supply issue affect a laptop not able to access the BIOS?
great video. You have a great voice for video.
No matter what probes you use, there is an easy way to "calibrate" them out:
Simply put them next to each other on the same pad. This is your "Zero-Calibration". Whatever you measure there is just the resistance of the probes + contact resistance of the pad you're on. After that, simply subtract that from whatever reading you take and there you go. I bet, your DMM even has a "REL" oder "Delta" button you can press, then the DMM does the subtraction for you.
I need to dig out the manual for my AN8008 because I can't find the REL function. I can't believe it doesn't have one though, seems like something all meters have!
@@Adamant_IT Not necessarily. If they have, they usually have a button just for that or at least as 2nd function of some button - in that case it should be written somewhere on the buttons. It might also be just a "Delta"-Symbol, so the triangle.
However, I had another thought about that topic and at least in your case here, there won't really be a way to use this kind of "triangulation". Here's why:
As you noticed, depending on the pressure you put on the probes, the reading changes by more than 100 mOhms. This won't really change, even with really good probes. On the other hand, the big power-traces or power-planes on a (laptop) motherboard will have single mOhms or a couple of 10s of mOhms at maximum from one side of the board to the other. So you will always end up with a measurement error, that is way higher than the slight changes in the actual resistance reading.
You would need a proper low-resistance measurement setup, so 4-wire measurement and about an amp of current. That would not be something, that could be done easily and even then, the resistance of your "short" might change as the faulty component heats up, so you still end up with non-conclusive results.
I tried a couple of times to narrow down the position of a short like that. It works out sometimes, when there is other components involved like ferrites, but with just traces, I never got anywhere. It confuses me more than it helps, because every time you see a different reading, you try to make sense of what that means, which most of the times is a red herring.
All in all, I think you don't need to spend money on a better DMM or better probes. You might need thinner probes like Louis uses, if you really want to go to town on SMD stuff.
@@NebukadV Some bench DMMs use a selector knob labeled "LP accompanied by the capital Greek letter omega, perhaps standing for Low Power Ohms" for resistance measurements less than 1 ohm. It is easy to deduce that LPomega DMM Bank = REL for portable DMMs. Another way of saying it, I do not occupy those functions because your answer is completely correct in the practical activity. As an example I will assume the resistance of the test leads is 00.2 ohms and (16:12) the meter reading at that point on the Mosfet indicates 1.0 Ohms, so 1.0 - 0.2 the actual resistance that exists is 0.8 Ohm.
On the other hand, according to you, Graham doesn't need to spend money on another DMM or test leads either.
There are MilliOhm Meters like the Vici VC480C+ model.
Finally, thank you very much for sharing your answers with us and I mean it with absolute sincerity. All the best.
I always use 10uf 25v or 30v on those main caps.
Especially when you dont know or have schematic
More repair videos!!
You're the best😊
I have a voltage injector, example of a problem short to ground, where should i attach the positive wire on the board, please reply thanks
thanks for sharing us termal cam help a lot thanks Adam any link for termalcam you used
I have a Flir One, but I don't think I'd recommend it. It's finnicky and lacks a lot of features. However, I've not tested other cams to see if those are any better.
All leads have resistance. You need a meter with 4 wire probes for low R measurements. 2 wires are used to sense and compensate for the lead resistance.
True. The question is if expensive leads can get it much lower than my cheap ones, or at least give more reliable contact at the probe points.
@@Adamant_IT I think very low ohm leads would be too thick and unwieldy (or short), but there are meters with a "relative" button. It can be used to zero out lead resistance by measuring the leads shorted together first.
Based on another comment I saw, this seems to be the key. Sadly it appears the AN8008 I use doesn't have a REL function, or at least I can't find it with the obvious buttons. Going to look into it though 👌
You need a 4wire ohms measurement to achieve your required accuracy.
Not a fancy probe, rather somewhat special.
The important thing is, that your meter must be born with the 4wire measuremnet capability.
They tend to be expensive.
Hi and thank you for a great video! are you still using Hanmatek Bench Power Suppy as your main power suppy?? as I am thinking of buying one and would like to know if your still happy with it?
Yes it's still my main! It's not super smooth for ripple and stuff, but that doesn't really matter for basic workbench use like this - would only matter for laboratory work.
a very intriguing one, this ,,btw, was it still running win7?
So love your videos, have been watching you're channel for over a year and noted that the subscribe button was red..... I'm sure I was subscribed. Did youtube flush all my subscriptions again? I hope not. Anyway subscribed(just in case I had missed subscribing for over a year lol) again... hope it was me missing it and not the google scrubbing my subscriptions...
I would love to see a rosin atomizer for such partial short search. It's not very expensive, and I wonder how would it do.
please pleaaase just buy a fluke!!!! i know i know, i watched the whole vid heard your words on cheap tools and completly agree. but you also have to then also agree that your a professional my guy and thats your number 1 tool ;). im an technician myself and your damn right i buy a facom over a hally advanced. theres no problem with them at all,functionally 99% the same. but its that 1% that counts when your in the buisness. your already an amazing dude and love your vids i just hate seeing you be a tight **** lol. keep it going my dude your awsome.
'A Fluke' is never the correct advice.
Fluke has plenty of models that are less suited for electronics repair even than the meter he has now.
And quite a few come standard with really really bad probes, but you still pay the premium price...
So without mentioning a specific model, specific probes ets, it's just not good advice. Ever.
And if you're not a big corporation that cares for multipackage calibration programs, legacy support and availability, there are better meters out there for 1/3rd of the cost.
i enjoyed that
hi could you tell me what type of webcam are you using i want something that i could zoom in closely for smd components
I use a Logitech BRIO. Most Logitech cams can do ridiculously close shots if you use Logitech Settings or Logitune to manual-focus them. The zoom isn't great though, so keep in mind the camera will need to be very close to the board.
could u plz use a reliable multimeter and prob to compare resistance measurement and explain how to use resistance to discover shorts allover the board and the actual reading
Jeezus my matematics suck hard but love this troubleshooting vídeos.👌
awesome
Feeding the algorithm. Great video!
Good!
What hot air station is that? Almost looks like a JBC but it doesn't seem like you're using anything else of theirs?
PS: I highly recommend ProbeMaster. They have an SMD kit that is around the price you mentioned which gives you multiple replaceable tips of 4 different sizes and dimensions. They're perfect for board troubleshooting reads. Pomona would be my 2nd choice.
Hello I love your calm methodology for fault finding. Do you have any details of your cordless soldering iron?
I use (interchangeably) a Miniware TS100 or a Pine64 Pinecil, they're not cordless, but have very broad power inputs, so they can run on anything from a 19v laptop charger to a 4-cell Lipo batt. Tips are cheap and widely available.
@@Adamant_IT Thank you - On it
literaly i saw the video today and i encounter in the trash the same laptop with the screen falling apart
What soldering temperature are you on?
I never saw you using an ESD strap, is it not required when working on hardware ?
I have a similar hp which problem is the USB is not working.
I checked all the USBs but yet still no response.
I do need 😩 your help
I wonder to find component you could use a Wheatstone Bridge with current injection on faulty board ,Ballance the wheastone bridge on first test location .try another location see if higher or lower.use short good quality leads that dont very in resistance (thick wires).I think you would have to test directly across capacitor or suspected device that you think could be short or near short.
No need for a bridge. Inject the current, set meter to mV, and measure voltage at various points on the board, lowest voltage is the short location.
I have 6-7 bad laptops, an only on one found a shorted cap. Removed it and laptop started bun no touch or keyboard. The others start but no picture.
What is the name/brand of the electric screwdriver you use?
Sequre SQ-ES126, not the cheapest, but it's quick and so far very reliable.
Affiliate link: sequremall.com/collections/screwdriver/products/electric-screwdriver?ref=fl20o11jut
How do you know that the resistor is a current sense resistor and how do you know which ones are for that purpose? Thanks for the video.
Most resistors on a mobo are very small black SMD parts with no markings. Current Sense resistors (aka Shunt Resistors) are fairly large, and often 4-pin (two large and two small). They often have a resistance marking on them, which will be a very low value, like R050 (0.05Ohm). All of those signs combined with the position on the board (bridging two large power rails together) should help identify them!
@@Adamant_IT thanks for your time.
Do you allow people to ship Laptop's to you for repair!? I am having some issues that can't be solved by repair shops in my area. Cheers
Probemaster probes!
hi adamant IT, i just wondering what are the rating of a partial shorted motherboard in diode mode??
hope you notice my question
More power!
I very rarely use diode mode. It's much faster than resistance mode, but you need to know the readings. I think it's more effective when you work on a narrower number of devices, like only apple or something, where there's less variation.
Dear princess Celest, I didn't learn anything
My probs get .04 ohm. But i did spend a hundred. I wanted the beep on diode feature and other things
If only the AN8008 and my AN8009 provided a way to zero out the ohms measurement, to compensate for the probes!
The ohm value of your probes can just be deducted from the value you're measuring since they're in series.
you said we cant inject voltage when cpu/gpu/pch are shorted. can we disconnect the cpu like removing the coils(Inductors) to be able to inject power?
If the main-rail resistance is the same as the CPU/GPU, you're shorted through one of the mosfets. At this point, you've already found the fault - one of the mosfets. So you don't need to inject. This is often unrecoverable, as 19v from the main rail will have gone into the CPU/GPU at some point.
@@Adamant_IT Today I removed the coil from CPU and GPU and I no longer have short to the main-rail the CPU "11800h" is shorted to the ground and showing 0.3 ohms, GPU "3060" 0.5 - 0.6 ohms. do you think the CPU is burnt ?
P.S. I don't have mosfets I have SIC634, didn't see any short to it
I have a HP laptop with no power charge light on it too but I don't know what to do with it..