I recently bought a fully working macintosh plus.
with that, another macintosh plus came in ok cosmetic condition but the owner said it wouldn't boot...
when i plugged it in and flicked the switch, it chimed normally, showed the memory check diagonal lines and then:
it showed the blinking disk icon... but
1. it was not blinking... just the question mark standing there (Cpu freeze?)
2. the background was solid black instead of dotted (Bad ram?!)
Opened it up, examined everything inside... nothing special, looked quite clean, original caps were there.
Cleaned the ram slots and SIMMS and reseated and cleaned the HI en LO rom chips.
Then the second problem ocurred... when i turned it on it would first beep fully... and then really reapidly start to reboot itself...
sometimes when gently knocking the analog board side of the case would make that stop and allowed it to fully boot... (loose connection in the power to the logic board?)
also when it got to the screen with the steady disk icon i lifted up one side and put it down again with a little thump, just to see what shaking did to it.
the CRT image started to wobble, did it again, CRT went black and it started to boot loop again.
maybe also useful: when it would boot loop you can hear the crt power up *blip* *blip* *blip*
Any idea's where to start with this?
my own suggestion would be to investigate the analog board... but i very scared of the high voltage part.
with that, another macintosh plus came in ok cosmetic condition but the owner said it wouldn't boot...
when i plugged it in and flicked the switch, it chimed normally, showed the memory check diagonal lines and then:
it showed the blinking disk icon... but
1. it was not blinking... just the question mark standing there (Cpu freeze?)
2. the background was solid black instead of dotted (Bad ram?!)
Opened it up, examined everything inside... nothing special, looked quite clean, original caps were there.
Cleaned the ram slots and SIMMS and reseated and cleaned the HI en LO rom chips.
Then the second problem ocurred... when i turned it on it would first beep fully... and then really reapidly start to reboot itself...
sometimes when gently knocking the analog board side of the case would make that stop and allowed it to fully boot... (loose connection in the power to the logic board?)
also when it got to the screen with the steady disk icon i lifted up one side and put it down again with a little thump, just to see what shaking did to it.
the CRT image started to wobble, did it again, CRT went black and it started to boot loop again.
maybe also useful: when it would boot loop you can hear the crt power up *blip* *blip* *blip*
Any idea's where to start with this?
my own suggestion would be to investigate the analog board... but i very scared of the high voltage part.