So I have a problem with my old laptop. Internal monitor is not working. External is working. So I tried to understand what's the problem.
I tried to check if inverter is broken. It get's a good 19V DC voltage on VCC, but BackLight pin has 0V. That's the inverter input pins. So I believe the monitor controller doesn't enable backlight. So there could be issue with the main monitor circuitry.
Then I tried to see what's going on with monitor data pins as I don't even get dim image which basically says that the issue could not be in the inverter. I have noticed that monitor circuitry doesn't get VCC3.3V from the motherboard. It does get EDID voltage, bet not VCC.
It's getting more difficult to track where is the issue as the track goes back to motherboard. I believe that one of MOSFET switches could be broken near the lcd socket therefore not providing power.
Long story short, I want to try to feed 3.3V into monitor circuitry VCC pin from external power supply. Is it safe? Any comments on that?
I am talking about two different pinsets. Again.
With inverter I get VCC, and I dont get the rest BKL and ADJ.
With video data pinout I get EDID but not VCC.
I don't have datasheets. So far I traced the problem with multimeter and pin names near sockets.