Liquid-damage A3114 M3 Air with CPU throttling (820-03286)

[sekidata]

This A3114 15" Air came in with liquid damage, mostly in the trackpad circuitry area. The damage was repaired and trackpad functionality was restored.

The machine acts completely normal except for a much lower than expected CPU speed. Using Cinebench, the machine’s CPU ranking is 1201, compared with the expected 8000. It passes Apple Diagnostics and shows no errors.

Any suggestions for troubleshooting the throttled performance?

 

[2informaticos]

Did you only work on the MLB?

Test with known good trackpad board and flex.

 

[sekidata]

Yes, only the logic board was affected. Trackpad & cable are known good parts, tested on another machine.

 

[2informaticos]

Works from battery alone?
It is charging correctly?

 

[sekidata]

Yes, everything works perfectly; I have not found any issue other than the throttling.

 

[sekidata]

Apparently, the CPU reports that its base frequency is 0.7-0.9 GHz. Way too low.

 

[2informaticos]

Some SSD components are close to trackpad area; may be also affected.

Trackpad includes some temperature sensors.
Completely changing trackpad board and flex should discard such an issue.
Check all pins and traces for trackpad connector.