Should I try and fix our broken iMac myself?

Our “basement” computer, an Apple iMac G5, won’t boot up. It’s about 6 years old and there’s nothing vital on the hard drive. There is quite a bit of music I’d like to recover from it, but otherwise nothing is needed.

How hard/fruitless would it be to open it up and see if I can figure out the issue? I have some experience opening iMacs - I replaced the cd drive on our G4 - but that was a pain in the ass because everything was crammed into a small space. I suspect this would be more of the same. It looks like the computer is worth $300-$400 to replace, but I would guess it might be close to that to fix the thing.

What to do?

It’s quite probable that if it won’t boot up it’s the hard drive which is dead. It’s almost for sure a PATA drive, but make sure before you go spending any money on replacement parts.

If it’s not the hard drive, you can pull the drive out and attach it to another Mac with a USB to PATA adapter, and pull off any useful data.

If it is the hard drive, you can buy a new PATA drive for $30-50, reinstall the OS and your software, and have a working computer again.

You may be able to boot the computer with the OS CD and run disk utilities, or boot with some other rescue CD, and test the hard drive. If the computer fails to boot from the CD in a similar way that it fails to boot from the internal hard disk, then it is probably not the hard disk, and the computer isn’t worth repairing. If it boots fine from a CD, and disk utility, disk doctor, or whatever, says the drive is bad, or it just freezes while running the diagnostics, then it probably is a bad drive. Whether it’s worth replacing or not depends on whether you want the computer, or consider this a good excuse to get rid of it.

IIRC, those models were plagued with bad capacitor problems. My son-in-law used to by them for a song, get a capacitor kit online and make a few hundred bucks reselling them.

The ‘bad caps’ are obvious when you look at the circuit board and iFixit’s web site might have step by step instructions.

This.
The hard drive is probably fine.
I re-cap G5’s for $150 (it’s a giant pain in the ass), but these day’s it’s not really worth fixing. Open the machine up, take the hard drive out, and sell it for parts on ebay. Then get a new machine, and use something like this to get your data off of the drive.