Help! 2007 core duo 2.7GHz iMac will no longer start.

Hi DBAqua,

Have been slow taking computer apart. I enclose pics (sorry the resolution is low), which show discolouration around points in the Power Unit. tarnish is visible in plates.

It appears to my inexperienced eye the power unit has died. If the images are good enough, I would like to get your opinion.

A replacement power unit cost is in the vicinity of AUD$130. I may find a better price but that remains an option.

I can also take the power unit out of the twin 2007 but I suspect a 2.4GHz may have a lower output spec spec than a failed 2.7Ghz.

I did not proceed to examining the CPU on the underside of the main board. All I can say is by contrast with the power unit, all the other circuit boards were clean and new.

The joys of tinkering!

Did exactly as directed BDAqua. No change.

Only sound is of fans.

Re GPU: Bulging capacitors as a result of excess heat? The iMac was running at idle 37° working around 58°.

Will keep your observation in mind when I open up on Wednesday and search for clues.

From previous usage before failure. Essentially it was a cool running iMac which was my reason for comment.

I shall take a look for discolouration, signs of heat damage and anything else and report an update.

You may be right. It has a twin with a 2.4Ghz CPU which is chugging along OK. Depending upon what I find inside the 2.7GHz I may simply retain one for parts.

I use Adobe CS5 on the computer and have no intention of paying monthly Fees to Adobe simply because Apple has upgraded their o/s. Call me a Dinosaur, but CS5 suite covers all I need for graphics. I may buy an old 2011 Aluminium iMac 27" 3.4 with Thunderbolt. Insert a SATA SSD and drive it from an external NVME SSD it will be a faster workhorse. With a 4 core Intel 2600 it will be plenty fast enough for my needs.

Solution: I bought a 2011 27" iMac 3.4 Ghz i7, for AUD $250, the last model capable of running o/s Lion. I need Lion for legacy software usage.

Good condition; good screen for its age, (all the Apple LED screens were uneven in my experience). Very clean inside, so I have been lucky to find a little used model.

Installed 2TB Samsung SATA SSD and I intend to drive the Lion o/s via external Adata NVME SSD in Thunderbolt port.

I may transfer the power unit from the twin 2007, 2.4 Ghz 24" later, just to get the 2.8 GHz core duo extreme running again.

Thank you for your comments one and all.