Lenovo Thinkpad W530 CPU VCORE STRANGE ISSUE

[rayliu11]

Would love some advice from the true professionals on this thread!

I have a W530 Thinkpad which has a puzzling issue that I've spent the week troubleshooting.

The laptop would refuse to start up unless the board was slightly pressed down in a certain area. I spent a very long time trying to pinpoint where to push on the board and pushed on various components to see if it was a contact issue. The location couldn't really be isolated.

When it refused to start, CPU VCORE would not come on. The Discrete GPU VCORE Power Good comes up along with the PCH Power Good as well. On the CPU DC-DC Converter, the Enable signal is pulled high as well. The signals would come up for a second or two before the board shuts down when VCORE doesn't come on. If parts of the board are pressed from certain angles, then VCORE comes on and the whole board powers up. It has been near impossible to pin point which component is making bad contact.

Schematics are attached.

[MOD EDIT] Link to schematic https://www.badcaps.net/forum/troubl...-thinkpad-w530

[FrozenHaxor]

Re: Lenovo Thinkpad W530 CPU VCORE STRANGE ISSUE

I've replaced several ThinkPad boards with directly soldered BGA CPUs due to failed connection between the CPU and the board since they use a tragic epoxy-like underfill that makes it impossible to reball, and those thin CPUs are a challenge to reball as is, their asymetric construction makes them prone to warping during the process. I consider attempting such repairs a waste of time and just replace the entire board if possible.

Often when you try to desolder those CPUs with 100% underfill in the BGA layer you will either rip parts of the board off, rip pads off or rip traces off. They never came off cleanly for me, something always gets damaged.

[rayliu11]

Re: Lenovo Thinkpad W530 CPU VCORE STRANGE ISSUE

This board has a socketed CPU so I'm not sure how a BGA failure would occur. I have tried multiple CPUs with the same symptoms.

The board also has a K1000M GPU. Could a failure on the GPU cause it to not have VCORE and shut down like this?

[mcplslg123]

Re: Lenovo Thinkpad W530 CPU VCORE STRANGE ISSUE

Yes GPU failure can cause this symptom. Try mildly heating the gpu(Dont overheat to kill it) and see if it makes the difference.

[FrozenHaxor]

Re: Lenovo Thinkpad W530 CPU VCORE STRANGE ISSUE

This board has a socketed CPU so I'm not sure how a BGA failure would occur. I have tried multiple CPUs with the same symptoms.

The board also has a K1000M GPU. Could a failure on the GPU cause it to not have VCORE and shut down like this?

Definitely, those BGAs pose same problems on those boards as CPUs, does yours have black underfill under the GPU?

[rayliu11]

Re: Lenovo Thinkpad W530 CPU VCORE STRANGE ISSUE

It does not seem to make a difference when heating the GPU. The past day, I actually managed to use the schematics to disable the GPU. I have removed the inductors that provide GPU Vcore and the GPU no longer heats up on boot. However; the symptoms are still the same, requiring parts of the board to be bent for it to boot up on the integrated graphics.

[FrozenHaxor]

Re: Lenovo Thinkpad W530 CPU VCORE STRANGE ISSUE

Do you have access to freeze spray? Sometimes it can pinpoint fault point really good as it causes rapid dimension changes of materials from temperature difference. I often use it.