Godsdammit it should not be so hard to replace a battery! I can't even find the damn thing!
Ahem.
Previously on LJ, I related the strange temporal misplacement being experience by my iMac. Nudged by
morniendil I finally investigated the battery option, and it does indeed appear that the battery is the problem.
Googling started well with a step by step guide to replacing the battery. I then went looking for the battery. The backup battery is, as it turns out, a standard CR2032. So if you ever need one pop out to your local electronics store and get one for less than £2. This will save you £25 on the standard price for an apple part-number labeled battery, or £40 off the most extortionately priced one I saw. This took quite a lot of surfing to find out.
During that surfing, I discovered that there also seemed to be another battery, the PRAM/clock battery. This of course is the one I actually need to replace. It is also a fairly standard 3.6v lithium battery available for less than £6, do not pay £50+ for one.
You're not supposed to replace this one yourself, so there are no official instructions. There are also no unofficial instructions that I can find but how hard can it be to replace a battery? Apparently there is some danger of explosions, according to one website, but another asserts that the process is easy.
But where is this PRAM battery? I've found it for the previous generation of iMacs, for the Powermac, and for the G4s, but not my 20" G5 iMac. Many people talk about replacing it, but no one speaks of its location.
Still, how hard can it be to find it? It's not a small battery relative to the size of my case.
Ha.
Opened up Fafnir, a painless and easy task. Located the backup battery easily and replaced it just to be sure. Then proceeded to peer into every nook and cranny, removing protective cases that used multiple different security screws in an attempt to thwart me, but all to no avail. Where the hell is it? Unless it's snuggled under the CPU heat sink or inside the power supply I just can't see another battery in there anywhere.
Current status: I no longer get pre-1970 date warnings on start-up, so apparently the back-up battery handles something. I'm still getting random time shift during sleep though.
If the PRAM battery exists in my iMac, it is confoundedly well hidden. If it doesn't, then why the hell is the clock still playing up?
I do not want to pay £60 in labour just to have someone replace a battery for me!
Edit: And for anyone wondering what it looks like: