iMac not turning on, Service LED#1 blinking
Hi,
would appreciate any comment/help about the following issue:
I got an iMac 27“, Late 2015, CTO. Display had a transport damage. Removed screen and tried to power on, service LED#1 is only blinking, if I press the power Button for a longer time, sometimes the LED will just stay on, sometimes the LED continues to blink. I can hear some strange noises from the PSU… Did anyone experience a challenge like this, should I try another PSU or could this be related to a faulty logic board? Could a faulty CPU be the reason for such a behavior?
Appreciate any support,
thanks,
marcus
Update (06/12/2019)
Hi,
just swapped the PSU against a known good one, same result, please see the video:
I guess it is Logic Board related, could this be a faulty CPU?
Service LED#1 is blinking, Service LED#2 is frequently and very briefly flashing (almost unnoticeable)
Any ideas?
Regards,
Marcus
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8 commentaires
Any update to this problem? I have an early 2009 machine with the same symptoms. I do not have a new power supply to test but I understand you tried a new PSU on yours and it made no difference. Please provide an update if you have more information to share.
par Larry Jorgenson
Hi Larry, yes, I have exchanged the PSU against a known working one, as this ended up in the same result, I assumed that the CPU might stopped working. Also exchanged the CPU against a known working one, same result, so I give up now. My last try would be to replace the GPU, and maybe this will be a safe bet that this will be the faulty part, but as the GPU is soldered to the board, I do not have the required machinery/tools to do so, will now replace the whole board.
Regards,
Marcus
par MacMarcus
@macmarcus Boo. In my case, I don't think the machine is worth the effort to repair. Good thing I only spent $20 buying it. One difference I note between mine and yours (based on the video), my LED is flashing probably twice as fast. Yours is a slow flash. Does the speed of the flash indicate any different problem?
par Larry Jorgenson
@macmarcus @larry767 - You both have bad logic boards. The GPU's in this series is soldered to the logic board directly. It does not have an MXM card unlike the older 2011 and back models
Power surges or a lightning strike likely killed both the power supply and the logic board power logic VRM's.
par Dan
Hey Dan, thank you for the comment. Does this mean a replacement of the GPU would do it or would you need to replace the LBP logic VRMs, which I would think is not doable?
par MacMarcus
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