How to troubleshoot dead laptop

[iret]

I have a Thinkpad A30p laptop which doesn't power up. The machine is in a good shape otherwise and I'm motivated to restore it, though I don't have any experience of dealing with completely dead laptops. When I press power button there's no any activity - there's no any light, no any beep, not even fan be spanning. It also doesn't draw more than a couple of watts from the powerline (verified with kill-a-watt). The power adapter is not the issue (verified it with another thinkpad machine), so I suspect that something is wrong with power delivery part of the motherboard. Would appreciate any advice on how to triage this going forward, e.g. how to check mosfets, etc

 

[ajacocks]

Welcome to the forum @iret .

First, you should get a copy of the hardware reference manual, which is available here.

Second, the failure is often in the power connector, where it is soldered to the mainboard of the laptop. If you look at this image of the motherboard, you can see that the power connector is soldered to the board in only a few places. When people plug the connector in too forcefully, or drop the laptop when it is plugged in, this often breaks the connector loose from the board. If this is the case, you can resolder the connector, or replace it, if it is too damaged.

- Alex

 

[DeltaDon]

To troubleshoot any laptop use need at least a voltmeter and some troubleshooting skills. In general, open the case and find the power input and see if the AC adapter voltage (often 19volts, but not always) is getting to the PCB. Look for 3 volts on one pin of the the power switch circuit. If there's no 3 volts then the power switch can't function. If 3 volts is there, does it get pulled to ground when the power button is pushed. If it does, then look for the main power voltage on the coils for each internal voltage supplies. A visual look at the large capacitors looking for bulged cap's or leaking caps can be the next step. Then since most internal PCB sub-power supplies are buck/boost and take the main voltage and reduce it for each voltage necessary for the various sections of the PCB to function correctly. Voltage on these supplies depend upon the main chip set and other component needs. If any power supply has main voltage on it's input and yet has no output then look for a short in that circuit. at this point, Without a schematic or most advanced troubleshooting tools that's about the limit of what you can do. Gook luck.

There's several laptop repair people on Youtube with hundreds of videos regarding repairing dead laptops. Watch about 50 or so and get an idea what it takes to fix a dead laptop.

 

[GiGaBiTe]

Check for suicide CMOS battery. There are many laptop models that won't power on at all with a dead CMOS battery. Unfortunately, many said laptops have said batteries buried away in highly inaccessible locations that often require partial or complete disassembly of the laptop.

I've revived many "dead" laptops that just had a flat CMOS battery.

 

[3lectr1c]

Also worth noting the A3x laptops are very prone to GPU failure, although I'd expect one to at least TRY to boot even if the GPU is dead, not just act 100% dead. It's a possible cause though still.

These don't need a CMOS battery to boot.