I’m working on a 820-01700 that was liquid damaged. The LCD assembly was fine looking, but the connectors were completely corroded and burnt away. The connector on the logic board looks perfect. I installed a new flex cable between the new display assembly (tested and working by the way) and still had no image. I was able to get an image on an external display, but at login screen it just appears to hang after entering the password and it starts to load. I know it’s actually running though as I was able to hear interface items as I was clicking around. I came up with the idea of using voice navigation to screen share and I was able to open the screen share on my iMac. What I see is a lower res. 4:3 image and it’s useable to navigate, but this was no solution. What could be causing this issue?
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820-01700 No display
- Thread starter Zebulon
- Start date
tcampbell34
Member
U9850 is dead and needs to be changed.
Looks like GPU problem, if you get bad resolution on external monitor.
VRAM issue also possible.
After login, machine tries to load GPU driver and then problem appears.
Heat the GPU/VRAM with quality flux; no more than 200 degrees, 15-20s.
If still the same, you can pass the board through ultrasonic bath too.
Inspect first for corroded resistors on GPU area.
BTW, do you get 3V3/5V_S0SW_LCD, at least in the first few seconds?
Check when you hear the chime...
VRAM issue also possible.
After login, machine tries to load GPU driver and then problem appears.
Heat the GPU/VRAM with quality flux; no more than 200 degrees, 15-20s.
If still the same, you can pass the board through ultrasonic bath too.
Inspect first for corroded resistors on GPU area.
BTW, do you get 3V3/5V_S0SW_LCD, at least in the first few seconds?
Check when you hear the chime...