PRAM Battery iMac early 2008

It is not correctly in place. The battery holder is broken. This image from iFixit.com shows an intact battery holder from an early 2008 iMac with the battery properly seated:

I've indicated with the red arrow that there is a "lip" that retains one end of the battery. That lip appears to be missing in your photos, allowing that end of the battery to sit too high.

That said, it's not yet clear to me that you have a PRAM battery problem. Please give more detail about the failure to boot. What does and doesn't happen compared to a normal boot?

With a bad PRAM battery you should still hear the startup chime and probably see the bootup screen (gray Apple on a white background). Intel Macs are much more forgiving about dead PRAM batteries than the "Old World ROM" Macs like the Beige G3 and earlier (larger pre-1998 except for iMacs).

Hi Faymondos,

Sorry to be late getting back. I find that in retirement weekends are the busiest time.

The iMac does not boot up at all

Let's do the steps. "Does not boot up at all" means different thing to different people and you got stuck with a process-oriented retired engineer. Sorry! 🙂

1) Do you hear any chimes--normal or otherwise--when you press the start button?

2) Do you hear any sounds that could be the hard drive spinning up or the fans coming on?

3) Does anything show on the screen? If so, what?

If the answer to all three is "no" then I am reasonably sure the power supply has failed. A dead PRAM battery would not cause an issue until until after the things on my "1,2,3" list have occurred.

Another thought if nothing happens when you press the power button. Over the years we've had the power cables on two iMacs simply stop working. Replacing the cable fixed the problems. You do not need the special cable Apple uses to make an attractive back panel. Any standard computer power cord will work.

Have you tried a SMC reset?

What battery did you use? If an exact replacement, it should sit correctly. Perhaps the old battery has leaked and the connectors will need a little cleaning/ scraping?