820-2936 screen changing colors

Kyle93

Member
Have a 820-2936 with no liquid or drop damage. When turned on the screen just changes solid full screen colors from red, green, blue, gray e.t.c

Could this be BIOS, PCH, or SMC issue? Never seen this problem before
 

Kyle93

Member
pram reset had no change.

with known good lcd the screen boots up white like normal but no apple logo with hard drive installed and no question mark folder ever appears without hard drive plugged in, just a blank white screen
 

2informaticos

Administrator
Staff member
"Pure" white usually means no 3V for TFT matrix; check for 3V at pins 2/3 of J9000.
Also check external video, as above mentioned...
 

Kyle93

Member
I get chime with or without internal lcd however i only get question mark folder on external monitor. I get chime with or without external

Yes I have usb activity
 

2informaticos

Administrator
Staff member
If connect original LCD assembly color test comes back?
Check continuity for all LVDS data lines of J9000.
Pay atention to L9080...
 

Kyle93

Member
board is in perfect shape with no drop or liquid damage, not sure how this could be a continuity problem.

Replaced L9080 L9004 and U9000 and still no question mark on good test lcd. Original screen is still going into test mode.

what else can I try?
 

Kyle93

Member
Just before I changed PCH checked for short one last time and it was gone somehow so tried new bios with new ME region. Now it chimes but cant get original lcd or test lcd to work.

Anything else to try or check or should PCH be replaced next?
 

Kyle93

Member
I have replaced PCH twice now and cant get a fan spin again. After first replacement thought maby bad pch or bad soldering since the light on charger came on but no fan spin and only drew .140amps so tried another PCH from donar board. I know my soldering is good but now I have no light and board only drawing 0.35 amps.

what am I missing? Are pads on board damaged beyond repair possibly?
 

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