iMac 27" Not Response/No Power

[ocelittle]

I just bought a 27" iMac off of Craigslist, 2010, and it was sold as not complete and without a hard drive.

I opened it up and was struck by the fact that everything appears to be in order, it has 16GB of RAM, and only the hard drive is missing. There were quite a lot of screws missing (only three holding on the panel, should be 8), and the isight was dangling loosely...

When I first received it, i tried to boot it up. No dice. Nothing at all. No beeps, no whir of the fan, just as if weren't plugged in. Figured that might be related to the hard drive missing, so I put in an old one that has OSX on it and still nothing.

I'm concerned that perhaps the Power Supply isn't working properly and/or needs replacing?

What should I be looking for in something like this? All cabling looks intact, and if not for the hard drive, I'd think it was A-OK. I know if I can find the source of the problem, I would be able to fix it.

Thoughts?

(EDIT)
The only sign of life from the machine is the HEADPHONE jack emitting a red light. Hm.

 

[phoenixsan]

Just....

two cents or ideas:

http://support.apple.com/kb/TS1587

https://discussions.apple.com/thread/2293156?start=0&tstart=0

 

[ocelittle]

Thanks for the links!

Unfortunately, however, I have been googling pretty much all day.

The lack of any noise at all when booting up gives me the idea that it is more than just a software issue.

I shall continue my quest to find the answer!

(FAKE EDIT)

I actually just tried the 5 seconds while off thing...and now I hear the FAINTEST of whirring from the computer when I press the power button. Very faint...

I'm thinking power supply.

(EDIT 2)

I pulled the power supply out and it looks clean. Honestly, other than the gaping hole in the middle (no hard drive) and the serious lack of screws in here (wtf)...this thing looks to be in great shape.

 

[Fishrrman]

This may or may not help.

Does it have a "motherboard battery"?

If so, have you tried replacing it?

 

[ocelittle]

This may or may not help.

Does it have a "motherboard battery"?

If so, have you tried replacing it?

I haven't checked. It's on the flip side of it and at the moment, I'm going to wait for the Power Supply I ordered from IFixIt (overnight shipping, will be here tomorrow), before I tear out the 'logic board'.

I took it into the Apple Store today and it was clear from the jump start that I knew more about this than he did. He said it was likely the Logic Board based on a handbook he referred to in the back. I have that same handbook (thank you Google) and read it last night.

It's either PSU or logic board. I hope it's the PSU...we'll find out tomorrow.