A500 repair - advice?

I've got an A500 that's mostly dead. Sometimes it wakes up when power is turned on, but dies 5 mins later. The power lamp kind of lights up halfway, but never hops that final bit and shines (if you know what I mean..).

I'm wondering what might be wrong with it. Apparently it has only 3 real parts; motherboard, floppydrive and keyboard. What are the odds it will come back to life if I replace the motherboard? I might be able to get one of these for $15 or less. I have another (working) A500, but it'd be nice to get this one to work too. :-)

It seems unlikely it would be the floppy or keyboard that's broken, or? Any ideas?

[Ilwrath]

I'm wondering what might be wrong with it. Apparently it has only 3 real parts; motherboard, floppydrive and keyboard.

Hmm.... What about the power supply?

If you have swapped the supplies and are running from a known good one, I'd imagine that it is something on the main board, then, but first, I'd certainly check that supply out!

[WarPiper]

the power supply maybe, umm umm are all the chips on the motherboard completely seated? maybe its a cia problem, have there ever been modifications to the motherboard?

[Damion]

 I had similar problems with an A500 once. It turned
out to be a cold/poor solder joint.                

[Stedy]

Try this file on Aminet,

Amigafix.txt       hard/hack   36K 123 Repair information for the A500, A1000 and A2000

A top tip is to remove each chip, one at a time, clean the legs with Isopropyl alcohol and replace.

I strongly sugest, that you change/Repair A500 PSU

I think the power supply is ok, it made my other A500 boot anyway.

What's a "solder joint"? English isn't my native language so don't know what you mean I'm afraid. :-)

Actually, one of the times I got it to boot was when I pressed on the chips and powered it up. It died 5 mins later though. But then again, it has booted without this procedure before. However, maybe cleaning their legs is a good idea? :-)

[zipper]

And don't forget to check the Agnus chip and it's PLCC socket - on some revisions the socket cracked very easily and 10-15 years don't help either. The chip may be lifted with a special tool or with a bent and trimmed paper clip as I did. And I fixed the socket with super glue and cable tie.