How do you diagnose backlight fault on iMac logic board?
I'm trying to diagnose a backlight problem related to an iMac logic board.
Symptoms/Notes:
- Boots fine but screen is black
- Image can be seen when shining a torch on screen
- External monitor works fine
- All 4 diagnostic leds are lit
Other things:
- LED invertor board is good
- Power supply good
- LCD and cables all good
- Cable when plugged into LVDS connector has continuity through all 30 pins
So the problem definitely seems to be with the logic board but I'm not sure where, or how to test further. I don't know the history of the board but it does appear to possibly have had the cables janked upon opening at some point as the LCD temp sensor is ripped off.
The only thing I can think of is to replace the LVDS connector but upon close inspection all joints look good, all pins have continuity through a cable, and the correct pins are grounded.
Is there anything else I can test? any other known logic board components, fuses etc. related the backlight?
I've been trying to find some schematics but had no luck.
Is this a good question?
1 Comment
It is a Core i5 iMac (2374)
by Shane Murphy