820-00165 Wont boot up - PPBUS_G3H 1.

[nelo1012]

This board came in for no boot, looked over the entire board, and no signs of liquid or burned caps, super clean, paying close attention I noticed C7372(PPBUS _S5_HS_COMPUTING_ISNS & ground) was burned, took it off and replaced it, still did not boot up, any ideas?

Board has also been ultrasonic cleaned after removed burned capacitor,

D7005

PIN 1 - 1.09V PPBUS_G3H
PIN 2 - 16.5V PP18V5 DCIN ISOL R
PIN 3 - 16.2V PPVIN_G3H_P3V42G3H

 

[SMMRepair]

Probably also killed the ppbus fuse (F7040? schematic not in front of me). Check both sides.

 

[nelo1012]

Yeah, brain fart again lol Thank you!!

I was thinking too much on this one,

 

[nelo1012]

ok, so I went ahead and replaced PPBUS fuse, without

C7372(PPBUS _S5_HS_COMPUTING_ISNS) being put on, put a new capacitor on, and it burned it again :/

not sure whats going on there, any ideas?​

 

[larossmann]

You likely still have a short circuit. What is the resistance to ground on PPBUS_G3H now?

 

[nelo1012]

I ended up leaving the capacitor off, since it there are many in the line, must have been a short somewhere,

thank you guys!!

 

[larossmann]

I still think you should put effort into finding a suitable replacement cap, but I suppose this can be considered solved now.