820-2936 slow

Jay

Member
Hi Folks,

Got a 820-2936 that runs slow yet passes all AHT and ASD (OS and EFI) tests.
Dirty inside but after a good cleaning no signs of corrosion. Same behavior with or without battery and other component isolation.
Figured this would be a sensor issue but no issues are found.

This was handed to me with reports of slow performance and occasional fan on max behavior (have not seen the fan on high myself).

Prior to cleaning the Mac froze when booting from a USB KG OS and restarted itself when I tried to launch an app, this behavior is gone after cleaning.
Also had the 3 RAM beeps once after assembly but reseating the RAM solved that. Battery is a compatible model A1322.

If not a sensor issue, what could cause the slowdown?
 

aprendiz

Moderator
I have had bad experiences with generic batteries, also check pins 6 and 10 from J3100, I have found those pins loose more than once...
 

Jay

Member
Checked the ram bay pins, they're all OK (I've only seen those come off in 2012's, is this a common issue with 2011's as well?). Tested with 2 other A1322 batteries and slow performance persists. If the SMC was at fault, wouldn't all the tests point it out?
 

Jay

Member
As far as I know, I’m the first one in here. I cleaned a few sections of the board with alcohol as they did not look 100% (dirt, no corrosion) and found that the whole upper section of the board is covered in a film of something greasy. Alcohol is repelled. It’s not visible but I can scrape it with tweezers, barely 1mm thick but I assume this stuff is under the SMC, CPU as well...

Without an ultrasonic cleaner ima have to pass on this one it looks like.

As for flashing a bios, that’s way out of my wheelhouse. I’ll get there but am not there yet :)
Thanks for sharing that though.
 
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