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 Topic: Mac IIci spontaneous power on (Page 1 of 1)
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  DerekLewis (Profile)
  16 MB
Posted: Tue Jul 19, 2016 12:14 pm

I have a Mac IIci which has been working well until the other day, I have found it had switched itself on while I was at work.

This could have a power surge, although later that day, I found that the computer and screen power lights on though no boot sound or screen image.

Could this be aging components in the power supply, a dying PRAM battery or components on the logic board causing this?

I would like to patch the machine up for one more project.

  feeef (Profile)
  64 MB
Posted: Mon Aug 01, 2016 7:06 am
Hi DerekLewis,

usually, it is recommended to replace the capacitors on this kind of aging motherboard. You may check if you see one that is leaking. I would also clean the board if it is dirty.

Also, replacing the PRAM battery is a good idea and very easy to do.

I hope that helps!
  ovalking (Profile)
  32 MB
Posted: Tue Aug 09, 2016 4:13 pm
I have a Quadra 840 with the same symptoms - powers up (via kbd or power button) but no chime and no video o/p.
It too was working fine (every day) until it froze once. I've never got it to start up again.

I have tried

- no PRAM battery
- new PRAM battery
- different PSU
- removed Nubus cards
- disconnected all SCSI devices
- reseat VRAM
- removed/reseated/juggled with RAM sticks
- replaced 15 capacitors (to the best of my ability!)

Sadly none made any difference whatsoever for me. It's a case of try as many things as your enthusiasm permits...
  DerekLewis (Profile)
  16 MB
Posted: Fri Aug 12, 2016 2:07 pm
Are there instructions in replacing the PRAM on this machine?

Also, I checked the board and found little dust though I could not see the caps below the power supply.
  DerekLewis (Profile)
  16 MB
Posted: Thu Aug 18, 2016 11:44 am
Okay, found a source for a replacement battery.
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