1 Diagnostic LED #1 ON only, won't power on
Symptoms:
- Diagnostic LED #1 is the only one lit up when plugged in.
- LED #2 remains off when I press the power button. Fans don't move. No response at all.
What I did:
- I referenced the service manual I found online.
- Power button is working properly (saw voltage drop when pressed)
- Replaced PRAM battery. Check the test pads next to the CPU and got 3V.
- Shorted the real-time clock (RTC) reset pads.
- Replaced the power supply.
- Check continuity on all the pins of the flex cable between the power supply and logic board. Cable is fine.
- Tried removing the SSD from the equation. No difference.
What else can I do to narrow down the problem before concluding that the logic board needs to be replaced? I don't want to shell out 250-300 bucks to get a new logic board yet. Are there other test pads or terminals that I can check if the voltages are correct on the logic board?
Any help will be appreciated.
Update - here are some photos of my logic board. I believe the model # is 820-4652-A. Nothing interesting to see here. Only LED 1 stays on when plugged in. LED 2 stays off when power button is pressed. Other than what I did above, what else can I do before I conclude that the logic board is dead? I thought LED 2 not turning on means the logic board is not getting the power it needs. So what terminals can I check to see if there is enough voltage on the logic board?
Es esta una buena pregunta?
893 
2.3mil 
@aannakin what is the 820-XXXX for your board? Since you already replaced and check everything else, the only thing left is the logic board. Post some good pictures of your board with your question. That way we can see what you see. Agregar imágenes a una pregunta existente
- de oldturkey03
@oldturkey03 Ammended my post with pictures and an update.
- de Annakin
@aannakin it's not always about "Nothing interesting to see here" when we ask to see a logic board. It's to help others out.
- de oldturkey03