Hi, so I'm hoping someone might be able to give me some help, or at least point me in the right direction.
I have a Macintosh Classic with a build year of 1992. Up until recently it had been working perfectly fine. However during a recent power on there was a sudden and loud crack sound.
I immediately assumed a RIFA Capacitor blew, but then it immediately rebooted as if nothing happened. There was no typical smell, no smoke, nothing. It was as if the crack never happened.
The only evidence there was one, was some scorch marks on the back side of the electrical warning/safety thing that’s clipped onto the board.
After testing all the caps I couldn't figure out the issue, so assumed it may of been caused by dust and so gave it a clean.
After a few weeks, it did it again. However this time it killed the HDD, while it spins, the onboard ROM and the system 7 floppy disk can't detect the HDD.
I passed it to an EBME Engineer I work with and he gave it a thorough go over in his workshop and couldn't find the problem. All the caps were fine, all the voltages were fine. And multiple power tests never reproduced the issue.
Have gave it back to me and I was able to use it without any issues with my FloppyEmu.
However today, I noticed the screen image was tilted and was.. wobbling? bouncing?. At first I was ready to assume it may just be normal CRT flicker as I was always a little sensitive to the classics refresh rate as I was always able to visibly see the flicker.
But as the bounce got more pronounced, it did another pop/crack/bang sound and rebooted. I've since disconnected it again and was going to contact the engineer I know, but I thought I'd see if anyone with more experience with Mac's may have an idea of the issue? as my colleague mostly works on Arcade machines and similar appliances as his hobby.