Where is the backlight fuse located on the logic board?
iMac 21.5” EMC2638, A1418 (2013). Main logic board 820-3588-A. Where is the backlight fuse on the logic board? Is there a board view available for this one please?
Pondering the possibilities of the mosfet being blown or could it be the backlight driver IC? I hope not. Finding a new LP8561 backlight driver may be tricky, and desoldering/re-soldering much worse.
That Q8102 mosfet is either blown or told to be turned off by the backlight driver. I wonder if there is a safe way to override the BKLT_SHUTDOWN signal to force the mosfet to turn on, which could confirm if it’s still ok or not. But that’s a p-channel and I don’t see how the backlight driver IC gives the mosfet its negative trigger voltage.
I've tried locating a datasheet for that LP8561 driver and couldn't find anything at all. I need to figure out how this thing works, so I can find out why it's not enabling the BKLT_SHUTDOWN signal.
All 4 diag LEDs are lit, when the screen is connected, so it's detected and power is supposed to be sent to it, but it's not. What could do this? What else am I missing?
I know the 12V does arrive on the Q8102 mosfet, but it's not enabled to pass through it. It could be blown, but at present I doubt it because the BKLT_SHUTDOWN signal is not telling it to turn on.
That signal comes right from the backlight driver IC, so either that's the one that is blown, or something is telling it not to enable the power to the screen.