820-3209 no chime

[Gmorb]

board came in with high fan spin no brain. once i got to work on it the board started working again it chimed and booted so since it had prior water damage i placed it into the ultrasonic to get rid of any lingering corrosion. upon putting it back together it wouldnt power on. after inspecting i could see r7141, c7105, r7151 and r7152 were gone. replaced all of those chips and now im back where i started. High fan spin and no brain.

i inspected the board and i dont see any other missing components

some of the capacitors near q7550 were corroded so i replaced those as well (c7516,c7517,c7555,c7558)

could bad PPBUS_S5_HS_COMPUTING_ISNS components being bad be the issue although the board is powering on because there are a couple corroded components i didnt replace for PPBUS_S5_HS_COMPUTING_ISNS only because they didnt look that bad and they were receiving their correct voltages.


cpu vcore is only 0.800v from my understanding it has to be around 1.25v

cpu and pch get hot so they are powering on.

any ideas?

 

[2informaticos]

Did you use UC whitout sweep function?
Possibly damaged/broken traces, apart of missing components now.
Keep in mind, UC can eliminate crap, but will not rebuild a trace.
In fact, no sweep can make more damage on a board than before...

Do you have USB activity?
Check the board without LIO flex connected, no trackpad, or other accessories.

 

[Gmorb]

My uc just has one setting on or off no sweep u mean just placing it in there and letting it soak?

Traces were just fine for that area i mentioned.

i do get usb activity

same issue with no accessories connected

 

[2informaticos]

If your UC doesn't have sweep option, you must change board position from time to time (30s is OK).
However, never let the board more than 10min in the bath.

If you have 100% USB activity, do PRAM reset and check if chime comes on.