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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?
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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
@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.
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@Corbin Titus - Can you redo the display cable connection on the logic board your image is too blurred.
Added anither one
Hey, I saw what you added to your post, and I had a few more questions, the logic board I'm using is actually a replacement one that was supposedly tested and working, is there anything else it could possibly be? Is there a way to test the backlights on the display manually?
I can also test the MOSFETs
Edit: also, the fans run at 100%, which leads me to believe that the motherboard isn't able to detect / pickup the temperature sensor on the LCD maybe? (I have everything else plugged in)
Also, the LCD temp sensor and the vsync cable are connected together, is it possible the cable / temp sensor is bad, causing the LCD not to light up and cause my fans to ramp up?
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