iMac Mid 2017 21’5 Retina 4k dead

[jasongoldworthy]

Hi guys I have been given the above iMac

and it appears dead I have replaced the psu with the same issue.

there are no led’s lit on the logic board at all

upon testing the psi I’m getting 12v out on most pins and even when I press the power on any idea what could be up with it ?
history behind it was that it turned off one day and never came back on ?

is she dead ?

cheers

 

[techiesteve]

The power supply will normally continuously supply 12v, as yours does, with mains power supplied. From your description it's likely the logic board has failed. An SMC reset often resolves iMac no power issues, but in your case it's not necessary as you have already disconnected the power lead when you replaced the PSU. Have you bypassed the soft start power switch by shorting the 2 pin connector in the top left of the power supply with a small screwdriver?

 

[jasongoldworthy]

hi Steve


thanks for the reply

and yeah I've bypassed the power switch and still no go.

I'm getting 12 volt well almost 12 volt which I would say is ok its at 11.7v on all pins

as I'm not getting any diagnostic led's to say there is standby voltage id assume the logic board is dead ??

although when I cracked her open there was no dust in there at all so id say she was barely used.

as I said the only history I have was that it was on one day and just turned off and never came back to life after that

but many thanks for the reply

Jason.