820-3115 no display

arnonabuurs

New member
Hi Guys, i have an 820-3115 with no display. Fan spins and i get a green light (no battery connected), mouse cursor lights up. 0V on PPVOUT_SW_LCDBKLT. I had no SMC_LID, some liquid going on in that area. Replaced R5071 and now have 3.4v here. Still have 0v on R1981 LCD_BKLT_EN which comes straight out of U1800? Maybe liquid bellow U1800 or is there something else I need to have in order for LCD_BKLT_EN to get high? Tested witk known working display, connected.
 

2informaticos

Administrator
Staff member
Do you get external video?
PRAM reset done already?

LCD must be correctly recognized before image and backlight activation.
So check some voltages at J9000, pins 3, 4, 6, 7.
Be sure no corrosion on that area.
Check all the traces, coils and R9008/09.
 
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arnonabuurs

New member
Did a pram reset and no image on external display. I found I have no power on PPVCORE_S0_AXG, I guess I need this for the display to work.

EDIT: I figured no AXG is normal when booting, so will check the rest. I connected a speaker and I do not get a chime and pram also doesnt seem to have any affect. Could it be an SMC issue as it seems it is not booting. WIth an external drive connected usually the blue light blinks when it boots but in this case it stays solidblue so it doesnt look like the board is trying to read the ssd drive.
 
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2informaticos

Administrator
Staff member
Seems that your ptoblem is not video related.
Your board doesn't work at all, even it turns on.
Do you have voltage at L7510/20?

Pin4 of U2650/60 gets high level?
Check resistances and traces around U6100.
Try other BIOS too.
 

arnonabuurs

New member
All resistors and lines from SPI ROM are ok looks superclean as well, will slap another bios on and see what happens.
 
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