Lenovo, No Power, Hunting for shorts - LFC
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- เผยแพร่เมื่อ 13 ก.พ. 2024
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Brilliant video even if it's just to show us all the flow of your thinking. A fail video is just as good if we're all learning from it. Cheers Graham.
It was an excellent run through on diagnostics of the process, thanks for that.
Your videos are extremely informative. No strings attached.
thank you for sharing your experience
Once again we see the consequence of having the PCH on the CPU module. If either dies you've effectively written off the laptop. Also, how much would it cost for the manufacturers to add a crowbar circuit to each of the low voltage rails?
Tell that to Lenovo,laptops with the square DC in, if middle pin touches the plus,it's kaboom baby for the sio chip,when they could install an overvoltage protection such as a simple zener diode....The answer is they don't care further that the one or two years warranty.
Adding short circuit protection would cost the company hundreds of billions of dollars in lost future sales. This is only the beginning. Get used to devices lasting just past the warranty period ;-)
Would we put the ZD right after the DC in Jack? If dc in is 20V, what would be a good value?
@optimizelogicrepair2784 don't remember exactly, but charger ID pin voltage in genral is around 3V
No-fix videos are also good, not everything could be fixed and as you said, we could also learn something from a no-fix. Thanks for your great work.
It's so cool to see your way of looking "blind" tru motherboard and finding a problem! Rly nice video!
I would've gone with voltage injection as well, because all the shorted dies I've seen have a localised hotspot rather than the whole thing heating evenly, ie, an actual physical conformation.
Great video Graham thank you for your knowledge 😊
Always interesting...If you want mesuring low résistance, use the "REL" function of your multimeter, it will help a lot !
You could have at least inject some power to the PCH coil and see with the FLIR the thermal footprint on the PCH crystal. This would be enough to swipe off any doubt that PCH is dead. Also, it would be a nice conclusion for the video.
U allways share more information thankx man
Man what a nice mouse mat. Creates a very nice ambiance I think!
Always interesting, thanks.
great explanation. thx
I strictly refuse to fix my own devices or those of anyone in my family. If I lived in the UK I would send them to you without hesitation. Another way to put it, I would accept your final opinion whatever the outcome, that is, you would forever be my trusted computer electronics technician. Thank you very much for sharing. Greetings from Mexico.
Graham, if you buy a universal laptop psu and lop off the output then wire on some connectors for a bench psu you get a universal DC charger with monitoring. Quick and easy costs about £20
In my experience, dead CPU and PCH became much more commonplace with 4th gen CPU/8-series PCH. So yes nowadays you can say it's been an issue for quite a while, but before that it was much rarer. Especially CPU, I've never seen a dead Pentium 4 or Core 2, even after taking 12V repeatedly, and I've worked on a lot of them. Back then you could have a dead ICH here and there, and I've seen a handful of dead 5 to 7-series PCH, but suddenly with 8-series the failure rate seems to have increased a lot.
Also I hate the U/Y CPU design with PCH on the same package (which incidentally appeared with 4th gen CPU), I can replace some simpler BGAs but these always give me trouble, always bends like crazy…
i've seen somewhere that from around 8th they decided to have the cpu or pch powered on 1.8V then have it internally stepped down but this would be a bad move as it's usualy power stages that fail....i'm talking only for mobile platforms.
Also since the tech gets smaller and smaller, the final product ends up becoming even more fragile and that's one of the main reasons why today's CPU dies immediatly after power stage failure.
@@Neo_AIO The FIVR is a thing in 4th/5th gen CPUs and some 10th/11th gen (Ice Lake/Tiger Lake). 12th gen has some similarities but not fully integrated. Some PCHs also have consolidated power rails.
I can't say if reliability is a concern or not though.
About the power delivery circuits, it's also interesting because somehow in my experience it's much less common to see failed discrete MOSFETs in older designs (excluding user-induced damage) even though they are supposed to be less efficient and with less protection than the newer designs with integrated power stages ICs. Well part of it is that on high-performance laptops they can see huge current spikes that weren't so common back then.
With FIVR, the voltage regulator on the board has an easier job, but as a result designs often use much weaker circuits (like a small single phase) and part of the strain is put on the CPU instead.
@@piernov ty for the information, isn't it dumb to put power management inside the hottest spot that could be on a laptop? Doesn't it make it more prone to failure due to heat?
I know chips have heat operation range but most of the times it's around 100°C max and the cpu often gets close to that mark....
@@Neo_AIO From the manufacturers point of view it's extremely smart to create a weak point. There are still old PCs from the early 80's working fine. My Space Invaders arcade game from 1978 is still working... I repaired it a few times but since it's all off-the-shelf parts it's always going to be fixable no matter what the issue is. Manufacturers know they messed up by making things last too long. Now they make them last just past the warranty period on purpose and having a designed-in weak point guarantees that ^_^
Reliable or original spare parts, i.e. CPU, APU, CPU&PCH together, etc.? In the web? Simple soldering process for replacement? The TSMC company on Wikipedia (read the full article) will give us an idea: starting "by contract"... ugh. All the best.
My multimeters cost between $30 to $50 - not really expensive but not cheap either and they work good - I have 2 that are analyzed
Some processors are designed when off to short to ground so they can release any residual charge. Im not saying its not dead from shorted power rail but id still get that chip replaced.
Very interesting thanks
Very nice video again thnx.
9:11 Smashed transistor/gate right here
Just sticky residue from the thermal sheet that was stuck to the back. Super annoying as I kept thinking I'd spotted messed up capacitors.
Done watching, thank you very much for the informative repair video. I have learned significantly more troubleshooting & repair lessons in this tutorial video and to your other repair videos as well compared to my ENTIRE 4 YEARS OF COLLEGE due to the rotten & outdated standards of education here in the Philippines. I hope you will soon have a mini-series for Schematic & Boardview-free Voltage/Power Rail Tracing[12V/18-20V Main Voltage Rail, 5V, 3.3V, CPU/GPU Core Voltage Rail, DRAM Voltage Rail, IGPU Voltage Rail, System Agent/Northbridge Voltage Rail, PCH Voltage Rail, BIOS Voltage Rail, Battery Power Rail], Proper method of testing/checking of potentially faulty MOSFETs & ICs/Controller Chips, CPU/GPU/PCH Reballing and BIOS Bin File Editing.
6:31 régulateur explosed!!!
19:50 umm yeah heh! never try to remove smd electrolytic caps with a soldering iron because you will just tear up the pads. Keep some common values in stock and just remove it with hot air and replace later. Or use low-melt solder to remove it with minimal hot air.
If you don't want to heat up the area you can typically twist them off and then just remove the pins with your soldering iron with no damage to your pads.
Did you just really spotted a shorted power stage just by looking at it's solder joints looking wanky? That was smooth. Good damn job, I'm impressed by your visual inspection skills.
This is kind of the takeaway I wanted from this video - lots of folks shouting "inject! inject!" but visual inspection and understanding the board is always safer than injection. Granted the CPU package was already dead, so injection wouldn't have mattered, but it's not a good habit to just start injecting the moment you find low resistance. You don't know where that low resistance is going, and it might be something that survived the fault, but won't survive injection.
The main problem is that CPU is soldered to the MB as in all modern laptops
well you can take that one step more. the main problem is electronics are now designed so they can't be fixed. often that simply means not adding any kind of short protection so when things do short it blows up the chipset / cpu and it's game over. manufacturers are not stupid. they don't want devices to last 20 years. they know they made things too good in the past and are rectifying it now by making things last just past the warranty period ;-)
I wish i had your injection checklist sooner
Yea I kinda didn't think of it until I said it in the video and thought 'wait this is a great idea...'
More on it next time it comes up 👌
2:42 Doesn't check the fuse...
Your right, shorted power stage equals dead cpu.
Interesting videos to watch fix or no fix. Tell the customer that Lenovo will gladly sell them another "sooner than you expect e-waste" laptop.
Check Startup Chip check 3 V line
Also Problem can be a haning startup Chip
Have you ever worked on high end Av receivers and amplifiers
Not really. I do get asked to fix them now and then, but I haven't sat down and learned diagnostics on them yet. Watched a little bit of content on it though, and seems like easy cross-training from laptops.
@@Adamant_IT , Yeah I think you would sus them out pretty quick , just that there isn't a lot of people doing videos , and the ones that do like to keep their cards close to their chests lol , and there is a bit of a movement these days wanting to repair older Units , like Technics,
The large cap was a polymer, it could've taken the heat just fine. just FYI.
Oh fair, I thought any of the can-style caps didn't like heat
@@Adamant_IT No he's very wrong on several levels of cluelessness. It's NOT polymer. It's an electrolytic. If you are quick and preheat the bottom first they can be removed with hot air without damage but if you apply too much heat it will expand and pop, or at the very least you'll melt the black part which is no big deal but visually not a good look. They are relatively cheap so just remove with hot air, toss it and replace it later with some common value new parts kept in stock.
They are aluminium polymer capacitors with a solid electrolyte that can withstand a great amount of heat. Normal electrolytics in these small packages are completely unfit for this purpose. Their ESR is way too high (and it's not like there are tons in parallel here to mitigate that) and as a result their ripple current rating is laughable. Look up some specs for such small SMD electrolytics for that capacitance and voltage... 100mA RMS max? You might just as well just place a piece of Lego on the board. No, they're deffo polymer, 'specially in a Lenovo, which isn't some cheap scam company that isn't going to do things right.
Why just pump some power in and see what gets hot with now available to anyone thermal camera?
Power injection is like using a calculator for your homework - you do it when you understand the problem you're looking at, and thus are able to validate the results the calculator gives you. If you don't understand the fault, you can't be sure that you're injecting in the right place, or if the result you see means anything at all. You might also inject onto a fault site that _could_ be salvageable, but becomes further damaged by injection.
Granted, I could've shortcut through a lot of this video by checking main power at the VRM inputs, then injecting and seeing the CPU light up - but then no one learns anything about diagnosing and tracing a motherboard, and then what's the point of the video...
2:20 why does that connector look like its not in all the way lol
I see what you mean, if you look closer (middle). You see two white "tab", preventing the connector to slide out.
no bench fee? how is that faring for you?
I find it amazing you do not charge for a "no fix" given the time and effort you spent diagnosing the high probability for the reason the unit is not working. I am not in the computer repair business, and this is not a criticism just my thoughts. Charge a nominal fee to investigate a client's computer. Besides your time there is your knowledge and a history of successfully repairing equipment, which has taken time to learn and execute. Then there are overheads that every business must pay. What is the difference between a nominal fee and free for a client wanting an item to work? I am unaware of the economics and/or competition in your area but £5 - £10 seems to me to be a very fair charge for even economically depressed areas in the UK.
I've been repairing laptops for over 20 years now and while I don't charge for travel time, some people do, I do charge for the time I spend diagnosing the fault even if there is no fix like in this case. I normally charge for 30 minutes, about GB£35, and will tell the customer the problem and give them an approximate estimate, if their device can be repaired. In a lot of cases the cost of repair is more than (for instance) a 10 year old Dell is worth so I help the customer with a new device and migrate their data over for a minimal fee. I'm happy to spend 5 hours fixing a laptop worth £50 if that's what the customer wants and I always give them all the options. I've had customers get a 2nd opinion and an attempted repair in some cases but I tell them if you take it to another repair place I won't be fixing their mistakes as some tech repair places will take any job for a flat fee whether it's economically viable or not. They then run into problems and the customer gets a more broken laptop back and a higher charge but that's their right, if they don't want to listen to my opinion after 20ish years of repair then go to another tech for advice.
Graham, when are you resuming videos of repairs again .....😊
Got some in the works, things just didn't align this week and I decided to focus on work instead of trying to conjure a video out of thin air!
look at to the component at 7:56 dude, there is an exploded component..
It's glue. There was a sticky residue all over the bottom from the copper sheet covering the back of the mobo.
Ha! 2nd!!! Great video!
Don't we all need a win...
@catriona_drummond: Hello. I'll never forget a short reply from you: "you just lost all your Italian subscribers"... that was great, lol. All the best.
@@AzuaraRuiz-md1bi Thanks :)
Disconnect the CPU coils
I love these small Lenovo's but their SOOO unreliable.
thank you for the detailed explanation . To save time and also to get to the transistor / mosfet / capacitor part of the short.. th-cam.com/video/BeEVzEx08iY/w-d-xo.html ... inject in the first short you find 0.8V 1-2A and a thermal camera.
Hello sir, I have change my laptop motherboard after that My realtek audio is not working. I have tried several ways but not working.
Model Dell latitude 7400 2 in1
Could be a driver issue or a broken audio chip or any one of about 50 other things. Take it to a professional for diagnosis as no-one can tell you what's wrong based on a mobo swap and a model number..
Why do people put stickers on they laptops it's nasty.
for the same reason people buy a new laptop after a year or two thinking it's old/useless and/or for the same reason people buy a new phone every year when the old one works just fine as-is. the reason being they are clueless.
Makes it go faster🤣🤣
Maybe because we’re not lemmings!
Hunting for shorts? In this weather? Can we see your legs first?