iMac G4 20 inch won't turn on?

[Retro Rider]

I got a iMac 20" that doesn't want to turn on. When I press the power button, nothing happens, no light no sound, no display, nothing. There is however a kinda beeping noise from what I think is the power supply when I put my ear close to the fan holes. I got it from the guy who said it also didn't power on for him. I tried the hairdryer method, nothing. It seems last night that if I pressed the button a couple of times, then it'll boot. Now that I'm trying it, it doesn't want to seem to power on. I striped the base screws to the ram (because of a crappy screwdriver bit) so try to keep teardown to a minimal if possible, or tell me how to remove them.

 

[jmb2011]

Sort of sounds like to me that something has gone wrong in some of the caps in the power supply section of the board. If I had to guess it's probably either a cold solder joint or a capacitor that has leaked, bulging, or stopped working. If you are handy with a soldering iron it may be worth your time pulling it out and at least reflowing the solder.

However, it would require major disassembly. If I remember correctly, the power supply board is closer to the top of the dome above the CD and hard drive and below the top vents and fan.

As far as the screws go, you could try drilling the screws heads out with a tiny drill bit. Just be careful not to go to far and ruin the threads in the mounts. You could also try an easy out bit or a left handed drill bit to reverse the screws out. However, again you probably want the bits to be fairly small.

 

[Retro Rider]

If you are handy with a soldering iron it may be worth your time pulling it out and at least reflowing the solder.

I'm not that good with soldering. I tried it once and fricked up my tip. I don't know what I did wrong but I don't want to destroy it even more. I would like to learn what/how to iron but most of the videos I found online I frankly found confusing.

reflowing the solder.

Wouldn't that be putting it in the oven? I've seen that before

As far as the screws go, you could try drilling the screws heads out with a tiny drill bit. Just be careful not to go to far and ruin the threads in the mounts. You could also try an easy out bit or a left handed drill bit to reverse the screws out. However, again you probably want the bits to be fairly small.

Actually I got them off. It took a long time with a wrench but I got them off its back on now but I made sure I can unscrew it if I need to (needs a ram upgrade)

 

[jmb2011]

Reflowing the solder is usually putting the soldering iron tip on the lead for each capacitor, heating up the surrounding solder back to a liquid state and adding a bit more solder and rosin to strengthen the bond.