820-3476 Freezes in OSX

ALB-Repairs

Member
Hi
Been an odd week as this is not an isolated incident.
We've seen 3 3476 boards that freeze in OSX, two were repaired for liquid damage, the other was free of liquid and physical damage, and arrived to us with this fault and no previous rework/repair. They are all 2.6ghz/8gb, All tested in there individual shells.

Ive tried reflowing the RAM on the non liquid damaged board, it had no effect on the fault.
Has anyone come across this fault before? its the first time ive seen this behaviour from this model.
 

Inwerp

New member
Just in case some one searches for this issue.
This is the display problem. I will try to investigate what's wrong exactly, but it works perfectly with my bench screen.
as far as i can see, it freezes in the moment it tries to adjust brightness, so it is some kind of sensor failure and as always - this look like another damn signature defect.
 

ALB-Repairs

Member
Just in case some one searches for this issue.
This is the display problem. I will try to investigate what's wrong exactly, but it works perfectly with my bench screen.
as far as i can see, it freezes in the moment it tries to adjust brightness, so it is some kind of sensor failure and as always - this look like another damn signature defect.

Holly thread revival,
if not for anyone interested i revisited what seemed to be the same issue recently.
I had an 820-3476 that would freeze as soon as you got to OSX, however if plugged into an external display would run fine.
This was due to corrosion under 8340 and a rusted pad. I think this freezing issue is caused by a bad LCD_HPD_CONN or DP_INT_HPD
 

Inwerp

New member
unfortunately my board is virgin-clean and it happens to run OK on my cracked bench test display, so it is not the board.
it is also kind of difficult to diagnose since verbose mode switches to the GUI just before this freeze happens. on the working display it looks like it changes resolution at the moment, but my eyes are not good enough to confirm it. this is definetely some fancy retina-shit and it should be fixable since invertor board is accessable and teoretically repairable.
i will check if i have something fancy going on on HPD line. (i found i rather stupid that hotplug line even matters for internal display)
 
Last edited:
Top