820-02020 - no image and cooler at maximum

Palhano

Member
The customer said they were using their Mac, the screen went blank, and the sound continued. When they turned off the Mac and tried to turn it on, it started with the fan running at maximum speed.

When checking the motherboard, I found oxidation on the UP800. I don't have this chip new, so I replaced it with a chip taken from the 820-01041 motherboard. But it didn't solve the problem. I tested the motherboard in another case, but the problem persists: the fan is at maximum speed and no display.

On the QP800:
PPVOUT_LCDBKLT - 0v
LCDBKLT_EN_L - 10.9v
PPVIN_LCDBKLT_R - 10.9v

Any tips?
 

Palhano

Member
Yes, I tested it.

I used a complete case, with everything 100% original. To test the cooler issue at maximum, too. But both issues persist.
 

Palhano

Member
I checked everything around the UP800, everything was perfect. I replaced the UP800 again for testing and also the LVDS cable, with no results.
 

2informaticos

Administrator
Staff member
Not sure if UP800 has firmware model dependant.
Should be good to test with one removed from 02020 donor board; just in case.
 

Palhano

Member
I discovered that the 3v3_s2 line was missing. So I replaced the UC710 and it worked.

Now I have a picture on the screen and the fan is on automatic.

Note: I'm using the UP800 from another board!

Thanks for the tips!
 
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