A500 resets by itself

[Sasuke]

A500 with floppy drive and 512kb expansion.
while running a game, it reset itself at irregular intervals.
If it hangs at the kickstart screen, it doesn't reset.
Sometimes it stays on for hours without ever resetting.

What could be the cause of this defect?

[pandy71]

Power supply (insufficient/unstable)? Cold solder joint(s)? IC's not being firmly seat in sockets?

[Sasuke]

Everything worked fine.

This glitch started after I removed the Cpu, Paula, Gary, Cia A, Cia B chips.
I cleaned all the chip pins with isopropyl alcohol. Then I put the chips back, fitting them well into the sockets.

Maybe I should have cleaned them with electrical contact spray?

[pandy71]

I would check which one can be responsible one, remove cover, take pencil with rubber tip and try to gently knock IC's and PCB in various areas until you find suspect then check if contacts are fine, they can be damaged in subtle way...

[Sasuke]

but is cleaning with isopropyl alcohol ok, or should i use the electrical circuit cleaner?
Could I press on the chips with my finger, without using the pencil eraser?

Among the chips I removed, which could be causing this defect?
I would like to avoid removing them all.

[pandy71]

Originally Posted by Sasuke

but is cleaning with isopropyl alcohol ok, or should i use the electrical circuit cleaner?
Could I press on the chips with my finger, without using the pencil eraser?

Among the chips I removed, which could be causing this defect?
I would like to avoid removing them all.

IPA is industrial cleaner used in electronics natively - i would not use anything else but i would avoid so called rubbing alcohol i.e. isopropyl alcohol diluted with water - avoid water as much as possible.

yes, key is to detect which one has faulty contact - sometimes working floppy may be enough to trig problem so mechanical force or vibration don't need to be high.

[giantclam]

Everything worked fine.

This glitch started after I removed the Cpu, Paula, Gary, Cia A, Cia B chips.
I cleaned all the chip pins with isopropyl alcohol. Then I put the chips back, fitting them well into the sockets.

If everything worked fine, why did you pull the chips?

On a working A500, at most I would 're-seat' these ICs....ie; spray chips legs with Deoxit or similar, use a chip lifter (modified spade screwdriver) to lift the ICs up around 1~2mm, then push the ICs back into socket ; doing anything more risks damage (C= used cheap & nasty sockets)