Apple A1502 very slow after liquid damage

[Jacksoft]

Hi all,
I have a trouble with a MacBook A1502 with 820-4924-A motherboard after it became in contact with some liquid (Picture attached, that's the only point where oxyde were).
I know that is a very critical point because that traces goes to the SMC and to the CPU.
The most oxyde is on XDP_CPU_PWRBTN_L and XDP_CPU_VCCST_PWRGD trace.
The PC is REALLY slow in any operation, but the fan works normally (it turns on only when the CPU is really stressed) and the CPU does not get warm, like it's running in "low power mode".
We made a check with AST in EFI mode and it found two issues: one with SMC (SMC can't communicate with one or more thermal sensors), and another with CPU thermal sensor.

I would ask where we can check and measure to determinate if SMC or CPU or both are burned.
I honestly suspect that the problem is with the CPU, considering the names of that traces, but I would do more checks before.
PS: Is SMC replaciable?

Thank you.

[mon2]

Re: Apple A1502 very slow after liquid damage

Review this thread:

https://www.badcaps.net/forum/showthread.php?p=1232091

Update this one after your review.

Be sure to clean up the green liquid damage with IPA and a cotton swab.

[mon2]

Re: Apple A1502 very slow after liquid damage

The SMC communicates with the sensors using smbus / I2C 2-wire interface.

Measure the voltage to ground of every smbus pair on the SMC which will be the SCL and SDA lines.

If any are stuck or missing, the sensor cannot be detected.

Post each measurement.

[Jacksoft]

Re: Apple A1502 very slow after liquid damage

Hi,
I'm sorry for the late reply.
In final we found that the problem is related to some BGA issue (not sure if under SMC or CPU), because without any screw around CPU/SMC the problem is not present and AST pass all test (ever the longer one).
Probably the Mac was also dropped, or the short damaged a solder ball and this happens.

Thank you.