Apple /// power supply schematic

[leaknoil]

I left an Apple 3 sitting there running memory tests while I went to the store. I came back to the biggest stink and clouds of smoke. C1 had decided to blow up in spectacular fashion. Nothing left but, a melted mass and a stink I cant get out of the table. If nothing it was a wakeup not to leave 20 year old electronics running unattended. Obviously it could have ended worse.

I'd love to give it another try and see if I cant blow up another one but, not enough left to see what its ratings were.

 

[tezza]

Ouch!

Yea, I don't like to leave my vintage models running unattended for that very reason. Which is why they don't get as much of a regular workout as they should.

Tez

 

[channelmaniac]

C1 is the same as C7 - 2200pf.

Technically you can run the power supply without it, but it's best to have it. You either got a power surge or the thing just decided to short the plates across the dielectric.

 

[Erik]

I had the same thing happen to one of my A3s although I was standing there at the time. . .

It was an easy fix, too. . .

 

[billdeg]

Happened to me twice
bd

 

[leaknoil]

Thanks for the info. Its an easy fix if I can figure out a way to stand the smell long enough to fix it

Three days later and the smell still makes my eyes water if I get too close to it.


I wouldn't think a surge as it had been running continually for about 20 minutes before it happened.

 

[Erik]

It's not a surge issue. It's just an old cap that warmed up, cracked and then smoked some oil.

I know the smell well.