820-4924 - Power cycling SLP_S5 & Clock

[gcain]

Hi Guys,

I'm back! but a little out of practice with the board repair thought process.


This board, originally it came in with a blown ground trace on U6100 which I repaired. The repair ended up being abandoned at it found a new home as my shop computer.

About two weeks ago I rebooted and it stuck on a black screen with a backlight, about 15 minutes later it finally chimed. A day later it decided to not resume from sleep and has pretty much never turned on again. Originally the CPU was getting warm and the fan would spin up, USB mouse had a red light. So it seemed alive, just never completed a post.

Now it's totally dead with a cycling SLP_S5 @ R1460.
All the all measurements around U1900 are bouncing too, but I think this might be a symptom of the real issue.

Any help appreciated.

 

[dukefawks]

Basics? Green/orange light, PPBUS, PP3V3_S5? PPVRTC?

 

[gcain]

wrong thread.

 

[gcain]

Get's a green / orange light as expected.

PPBus = 12.59.
P3v3_S5 = 3.33
PPVRTC = 3.33

I felt heat around L7095 the once time I plugged it in, but can't reproduce it again.

 

[gcain]

L7095::2 in diode mode gives me 0.095.
I think that might be a little low.

 

[gcain]

This ones to the junk pile.

I just smoked the board by misreading the schematic.

 

[gcain]

Actually, which stencil would I use for the SMC on this board?

I blew the SMC when I mixed up PPBus_G3H and PP3v3, might as well learn how to replace the SMC on this once since I have several donors.

 

[dukefawks]

If PPBUS got to the 3V42 line then there is a lot more fried than just the SMC. You will need to replace every single semiconductor on the 3V42 rail, I guess about 10 parts total, including Hall sensor for lid.
Use search function for SMC stencil, has been linked to multiple times in the past.

 

[gcain]

Yeh, that's why I threw it in the parts bin originally.

But figured I may as well practice SMC replacements on it since I have a bunch of boards the same and it's the one of the only repairs I've never done.

 

[dukefawks]

The thing here is, you are going to replace all these parts and then end up with a board that is still dead and will power cycle. Huge time waster board, unless you have nothing else to do just trash it.