saybur
Well-known member
I've got a problem child Power Mac 7100/66AV that I've been trying to fix for a while, and was hoping for some thoughts from knowledgeable people here about the next steps to take.
The issue: from either an ADB keyboard or the rear button, the system powers on (front LED lights, there's a slight "click" from the speaker, PSU fan spins up), but then nothing happens - no chime, no video, zilch.
When I first got this system, it worked fine; it had been in climate controlled storage and was apparently treated well beforehand, so fairly clean, no obvious cap issues, etc. I replaced the PRAM battery, re-applied some good thermal paste to the CPU per reports here & elsewhere about the stock stuff going all dusty, blew out the dirt that was inside, and ran it for an hour or so before putting it up on the shelf for an eventual re-cap.
After a few months of intermittent use, mainly swiping parts from it while I was working on other systems, the 7100 was no longer booting correctly and started exhibiting the behavior in the title. After checking the battery in-circuit (which read 3.6V) I figured it was just the usual Mac cap issues. So far, I've tried the following:
I'm not entirely sure where to go from here. Does anyone have any ideas?
The issue: from either an ADB keyboard or the rear button, the system powers on (front LED lights, there's a slight "click" from the speaker, PSU fan spins up), but then nothing happens - no chime, no video, zilch.
When I first got this system, it worked fine; it had been in climate controlled storage and was apparently treated well beforehand, so fairly clean, no obvious cap issues, etc. I replaced the PRAM battery, re-applied some good thermal paste to the CPU per reports here & elsewhere about the stock stuff going all dusty, blew out the dirt that was inside, and ran it for an hour or so before putting it up on the shelf for an eventual re-cap.
After a few months of intermittent use, mainly swiping parts from it while I was working on other systems, the 7100 was no longer booting correctly and started exhibiting the behavior in the title. After checking the battery in-circuit (which read 3.6V) I figured it was just the usual Mac cap issues. So far, I've tried the following:
- Replaced the electrolytic SMD caps on the logic board
- Tried to run the system with just the ROM SIMM, onboard video, and the soldered 8MB RAM
- Re-seated the ROM SIMM a few times
- Swapped the PSU with a known-good unit from a IIci (the 7100 PSU runs fine in the IIci, as I recall from work a few months ago)
- Verified that the HDD/CDROM power rail has good +5V & +12V
- Did an inspection of the board for obvious scorching, traces rotting, corrosion, etc.
I'm not entirely sure where to go from here. Does anyone have any ideas?