Model A1312 / Mid 2011 / 2.7 & 3.1 GHz Core i5 or 3.4 GHz Core i7 Processor

351 Questions View all

No diagnostic #1 LED on logic board

When the computer is plugged into the wall the diagnostic LED #1 is not lit. If I leave the computer plugged in for a period on time, usually overnight the LED1 light comes on and the computer starts and runs normally.

Based on the service guide, I replaced the power supply with a new one but continue to have the same problem. I have checked the cables into and out of the power supply unit carefully and they seem good. The next step seems to be replace the logic board.

  • Any suggestions other than replacing the logic board?
  • Anything I can do to confirm it is the logic board?
Answer this question I have this problem too

Is this a good question?

Score 1
Add a comment
Black Friday
Broken doesn't stand a chance.

1 Answer

Most Helpful Answer

Go to Page 23 in the Apple service manual which describes to the location of the PRAM battery. I would first try replacing it as it can create some odd behaviors when its low or dead.

Was this answer helpful?

Score 1

Comments:

What service manual and where do you find?

by

iMac 27" (Mid '11) - Apple Technician Guide {'11-08-29}. He implied that was what lead him to the diagnostics. So I figured he could reference it for the PRAM. ;-}

by

That is a good suggestion, tried it and still doing the same. I have a logic board on order.

by

Add a comment

Add your answer

Eric Hendrickson will be eternally grateful.
View Statistics:

Past 24 Hours: 0

Past 7 Days: 2

Past 30 Days: 4

All Time: 82