Simple Apple 2 PSU repair

Well, I finally had a chance to see a few of those infamous RIFA metallized paper capacitors first hand!

Yesterday, I had a look at two Apple IIe machines. One was from 1987. This computer works and is in really good condition and bears the signature of Steve Wozniak. I thought it would be a good idea to go and check for RIFA capacitors in there, but there weren’t any. Here’s a picture of its really clean power supply:

I am guessing that those two white things are the noise suppression caps.

The other Apple IIe doesn’t work. The person running this machine immediately switched off the mains line when smoke started coming out of its power supply. That’s good! The capacitor didn’t go short, and the fuse was still intact. Maybe it even reduced the amount of smoke and brown juice sprayed about its perimeter.

From the symptoms I’d correctly assumed that the owner had witnessed a RIFA capacitor explosion, so I came prepared by buying some replacement caps! I’d expected to have to bodge them due their size difference, but to my surprise, the PSU board had three holes for the noise suppression caps. The RIFA cap was using the outer holes (“holes 1 and 3”), and my smaller cap fit perfectly into holes 2 and 3! Cool beans.

Original RIFA cap (pin spacing of around 2 cm I believe) and replacement (1.5 cm). (The replacement cap has its X2-certification on the other side.)

The PSU had two RIFA caps. The one pictured above is “intact”, though it has a huge crack in its plastic case. Here are the pictures that we’ve all been waiting for, the exploded cap:

The ejected brown juice wasn’t too bad and cleaned up quite nicely.

Here is the computer put back together again, already performing advanced calculations.

The end.

Edit 2024-07-11: one more, an Apple II Plus

This guy’s power supply was riveted. What the actual? I think the screws used were some tamper-proof kind, too. The rivets were drilled out and the screws still wouldn’t come out, beyond a millimeter or so. So the screws were drilled out too. It was a bit of a nightmare. The label on the power supply said Astec AA1040. There were no RIFA caps in it.

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