IIsi powers on and off on its own

[CygnusTM]

Since buying this IIsi, I replaced the PRAM battery, upgraded the RAM (from 5MB to 17 MB) and recapped the PS and the system board. Before and after these modifications, it will randomly power itself on if left plugged in, and it will randomly power itself off while trying to use it. Sometimes, when I shut it off myself, it will turn itself back on immediately. (The power button is not locked in.). I suspected the switch in the keyboard might be the problem, but it happens with or without the keyboard attached.

Before I crack open the case to look around, I thought I'd see if anyone here could suggest a specific thing to look at. Thanks.

 

[joshc]

Did you also recap the daughter board that provides the soft power functionality in the PSU? Does your IIsi have a Sony power supply?

 

[CygnusTM]

Yes, I did, and it has a Sony power supply. I guess I should focus my investigation there?

 

[Byrd]

Check the continuity of the switch at the back - my recently recapped IIsi does the same thing, only if I get the switch in the right spot does it turn off. A future plan is to replace this switch.

 

[CygnusTM]

Check the continuity of the switch at the back - my recently recapped IIsi does the same thing, only if I get the switch in the right spot does it turn off. A future plan is to replace this switch.

The switch is now the prime suspect. I didn't have time to take it apart and investigate the switch, but I did have time to start it up and lock the switch in "server" position. It ran all day without spontaneously shutting off. When I get a chance I'm going to see if I can get some DeoxIT in there to see if that helps.