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820-4924 missing pm_slp_s3

S

shlom

Member
hello

having a strange thing with a 820-4924 (diffrent one from the one solved a few days ago)

after liquid damage, had a hard short to ground on PPBUS_G3H
the short to ground was solved by replacing the two mosfets - Q7310 and Q7320 from a donor board..

now i get 12.54v on PPBUS_G3H.

still missing the rails
PPVCC_S0_CPU - 0v
PPV5_S0 (come and goes, could be a bad u8080, don't have another to test currently, as of now showing 0.40v)
PP1V05_S0 - 0v
pm_slp_s3 - 0v


i got the fan spinning in some point, but no chime or sign of life.

could be damage to the cpu due to the short on PPBUS_G3H?
advice on what to troubleshoot next?
 
S

shlom

Member
hi john

actually the one that was making the short was the other mosfet - Q7320, when i pulled him out the short was gone..
i replaced q7310 just in case.. does that make any diffrence? or still RIP for the cpu?

also,
i notice now that when i plug in the charger i get PM_SLP_S3 3.3v for a few seconds and than it's gone..
 
J

JohnB8812

New member
If that one shorted, maybe a chance, but I doubt it. Replace Q7310, Q7311, Q7320, Q7321, and U7200 all at the same time and pray the CPU didn't get killed.
 
D

dukefawks

Administrator
Any "high side" FET shorting from PPBUS to any rail will usually destroy everything on that rail. So a shorted high side FET in many cases is hopeless. CPU Vcore is just a very common one and the CPU is easily killed.
 
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