Chosen Solution
Hey guys! So I have a 2011 21.5” imac I’ve been working on, and I cannot get the backlight working at all. I’ve been through 3 different LED driver boards, and even tested 3 different powersuppies. If I aim a light on the display at the right angle, I can see the apple folder flashing. Any other ideas on what the issue could be? Bad LCD?
I would focus on the cables and the connectors. How about taking some good clear tight shots of the cable ends and the connectors on the logic board side and the display side so we can see what they look like Adding images to an existing question Refer to this guide iMac Intel 21.5" EMC 2428 Display Replacement Steps 5, 6, 7 &8 Update (01/30/2021) @Corbin Titus - Still not sure, but lets assume the cables and connections are OK. Then we need to assume the issue is within the logic board backlight power circuit.
Using a DVM and a boardview drawing test the three MOSFET’s I’ve shown you here. IF this is beyond your skill set you’ll need to find someone locally to help you.
