820-3332 - occasional loud fans and laggy system

it-solve

Member
This Macbook has a previous repair around U9200/10, U8310/50 and U8900 ICs, and a battery replacement.
AHT is not initiating stating a missing .efi, TectoolPro 11 haven't detected any anomalies.

Replaced the trackpad and trackpad cable. It worked fine for a week and suddenly start running the fans on loud again. Intermittently it would calm down and then again would blast the fans with the same lagging. Other times would work and play videos with no issues for days.

Can't spot any corrosion on the board, although the customer mentioned spillage on the mac a long time ago. The keyboard works fine.

Wondering if anyone experienced or has points where to look for?
 

2informaticos

Administrator
Staff member
Install HWMonitor and check for strange values reported at the moment problem appears.

I strongly recommend to test with known good battery, not new.

Disabling GPU on this model is so easy.
Just to check if problem comes bak again, or not.

You can also try flashing new BIOS, with clean ME.
And see if ASD passes without errors.
 

it-solve

Member
Tested battery, which works on other mac - Still loud fans
Got gswitch software to switch between GPUs and left for a while - still fans loud
Looking at the sensor heat pipe incoming/outgoing air ones are off. Any idea where these sensors could be on the board (Q5502 / U5570 seems to be a candidate) and how to measure them in the case? Measuring without tpad/kbd will it affect? Usually, fans go loud when run outside of the case.



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2informaticos

Administrator
Staff member
Inspect Q5501/2/3 and their traces.

Do you get 128 indications even in normal mode (when no loud fans)?
Fans go high if trackpad is not properly detected.
 

it-solve

Member
It seems like the Camera is playing up. Disconnected and monitoring the situation.
Probably nothing can be done without taking up the glass and replacing the camera, right?

Thank you again
 

2informaticos

Administrator
Staff member
This points to ALS problem.
Reconnect camera and cutoff the traces from pins 5 & 6 of J3502.
 
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