iMac 27 2013 No Power

CRC2018

Member
Got a 27inch Imac in today which has no power. Customer says it was working fine until it was knocked off the table (screen is broken also but that's a separate issue)

I've opened it up and appear to have 12V coming out of the PSU to the motherboard and LED1 for standby power is on. When I press the power button nothing happens at all - i've checked the power button for continuity when it's pressed and it appears to be working.

I'm leaning towards maybe a PSU fault but I don't see many of these issues so would appreciate any guidance as to where I should check first as I would have to order a new PSU!
 

2informaticos

Administrator
Staff member
First of all, post 820-xxxx code of your board.
Next, tell us which schematic/boardview use as guide, if original not available...
 

2informaticos

Administrator
Staff member
Check if 5V_S4 tries to appear at L7650, when you press power button.
If nothing, check for pulse at pin 24/U7600.
ISL62383C fails too much in these machines...
 

CRC2018

Member
I shall check those thanks! Is there any easy way of testing the PSU's on these or is it a case of if it makes 12V it's probably fine?
 
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