820-3115 - sensors issue

[jadao]

This old board was coroded and had many issues to name a few:
3 bad sensors due to bad divider resistor and or traces and or sensor itself.
3 shorts firewire thunderbolt and IR chip
Bad backlight circuit with maximum of issue, fuse, sensing resistor, traces, driver chip enabler circuit
Bad charging circuit
CPU TON A and B
The repair went smooth, and last thing I tried was to test if IO0R sensor fault went away.

In ASD EFI the sensor section is sometimes missing.
When the sensor section decide to appear an I run the test all values are -124 Volts, Celsius, Amps or whatever value we are testing.

I am just about to abandon this board.
Any idea to check? something common must be related to smc...
Logicboard runs well...
Thanks

 

[2informaticos]

Check AVREF for SMC at C4921.
SMC requires this voltage for A/D conversion.
And of course, after so bad corrosion near SMC, remove and reball it...

 

[jadao]

Avref is 3.3V, Sometimes it wil himes sometimes it doesn't but all rail present including cpu vcore...
I Will reball SMC as corrosion got there for sure, I just found R5498 (DCIN Vsense) completely gone and bad looking TMS TDI TDO resistors...
I will report back. Thanks!