Back in January I got this iMac G3 for pretty cheap. It originally powered on but showed nothing on the CRT.
When I connected an external VGA monitor, I saw it did boot to the “No boot device” screen, which was expected since the original HDD was removed due to failure.
Eventually a MacOS install CD got stuck, so I opened it up and removed it manually. After that, the behavior changed. It now chimes with the green power LED, then as the external monitor briefly detects a signal, it shuts off.
If I try again right after, the power LED comes on but nothing else happens. No chime, no video, nothing until I power it off manually. After unplugging for a few seconds and plugging back in, it goes back to the initial state where it chimes and then shuts off when it should show video on both CRT and external display.
What can I do? I replaced the PRAM battery and it made no difference. It also shuts off before I can do a PRAM reset (Opt+Cmd+P+R), and the physical PRAM button hasn’t helped either.
Just now I did try leaving it plugged in for about an hour, which did make it able to keep being powered on, though nothing appeared on the CRT.
Trickle voltages seem normal, but when it reaches the “power LED only” state, the down-converter board voltages are lower than normal. After unplugging it for a few seconds it returned to how it was before, powering itself off after a few seconds.
When I connected an external VGA monitor, I saw it did boot to the “No boot device” screen, which was expected since the original HDD was removed due to failure.
Eventually a MacOS install CD got stuck, so I opened it up and removed it manually. After that, the behavior changed. It now chimes with the green power LED, then as the external monitor briefly detects a signal, it shuts off.
If I try again right after, the power LED comes on but nothing else happens. No chime, no video, nothing until I power it off manually. After unplugging for a few seconds and plugging back in, it goes back to the initial state where it chimes and then shuts off when it should show video on both CRT and external display.
What can I do? I replaced the PRAM battery and it made no difference. It also shuts off before I can do a PRAM reset (Opt+Cmd+P+R), and the physical PRAM button hasn’t helped either.
Just now I did try leaving it plugged in for about an hour, which did make it able to keep being powered on, though nothing appeared on the CRT.
Trickle voltages seem normal, but when it reaches the “power LED only” state, the down-converter board voltages are lower than normal. After unplugging it for a few seconds it returned to how it was before, powering itself off after a few seconds.
