A2442 - no internal display - external display working

[tawnytim]

This device is A2442, board 820-02098-A and came in with no power, liquid damage. I repaired the liquid damage and the machine powers on with chime but no internal display. External display is working.

 

[2informaticos]

Do you get 1V8 ad 3V8 at JP600?
Did you test with known good LCD assembly?

 

[tawnytim]

I don't have a known good display I do have pp1v8, but I'll have to pull the board to check for pp3v8, as it's on the other side of the board. I looked extremely closely at the display and cleaned it off. I can confirm that there IS picture on the display, just no backlight.

 

[2informaticos]

3V8 is also there, if you get image.

Check diode mode to ground at PPVOUT_LUXE; w/ and w/o LCD connected.

 

[tawnytim]

diode mode:
.550 LCD disconnected
.477 LCD connected

 

[2informaticos]

Which area has been affected by liquid spill?

Check if all resistors around UP800 have correct ohm values.
Also check UP800 solders and traces.