Got this Performa 578 a month ago on Marketplace for a whopping 50 bucks. It had been left outside and it showed. Dirty, gross, and it made a very concerning whining/arcing noise when it was on.
Traced the noise to a transformer on the analog board. If I pushed on it while it was running, the noise stopped. Couldn't source a new analog board or transformer, so I did the next best thing: wedged a piece of wood between the transformer and some other component and secured it with hot glue. Amazingly, that completely solved it. No noise, no display issues, it just works. (Second pic is the fix. My finest work. :3)
While I was in there I recapped the analog board and logic board (tantalum on the logic board). I also deep cleaned the entire case. The original hard drive still works, so I did a fresh install of System 7.5.3. The CRT needed some adjustment but man, these Trinitrons look awesome.
The plastics on this thing are BRITTLE. Every time I take it apart I make it worse. Tabs snapping, cracks forming around the case screws (one of the case ones completely shattered). I'm genuinely terrified to open it at this point. Is there any way to fix or prevent this, or am I destined to slowly turn the case into dust? I've heard people mention epoxy, or even baking the plastic?? Any advice is welcome.
Got a 32MB SIMM on the way to bump it up to 36MB. Anyway, 50 bucks well spent.