The Apple IIe personal computer was manufactured from January 1983 through November 1993. I purchased an Apple IIe several years ago and put it into storage at the time. I recently pulled it out from storage and began the process of refurbishing it. Part of that process was rebuilding the power supply, which I will describe here.

The power supply appeared to be original to the computer with a date code of 47th week, 1985.

Apple II PCB Removed from case. Original capacitors in place. Build Date 47th week, 1985.

Examining the circuit board showed that the electrolytic capacitors were superior quality United Chemi-con.

Original Capacitors in place, output side.

By contrast, the line filter capacitor was a RIFA film capacitor of a type known to fail. Cracks were clearly visible in the outer case of the … Read More »

The post discusses the condition of RIFA Y Safety capacitors, which were prone to failure due to a cracked outer case. The issues were reportedly resolved after Kemet acquired RIFA in 2007. However, flawed capacitors remain in equipment older than 2007. The author has replaced many such capacitors in various older equipment, improving their safety and functionality.

RIFA Safety Capacitor Failures have been documented by many of us who restore and maintain vintage electronics equipment. One very spectacular failure was caught live here: courtesy Dave Jones of the EEVBLOG. These capacitors were widely used in test equipment manufactured during the late 1980’s through the 1990’s. The consensus is that the capacitors fail because the outer case (presumed to be a type of epoxy) develops cracks which allows moisture to penetrate the body of the capacitor. This leads to internal short circuits which cause the capacitor to fail catastrophically. Because these capacitors are line to ground, they could see line voltage whenever a piece of equipment is plugged in, even when switched off. The crack network can develop to the point where large pieces of the outer case spall off, exposing areas of … Read More »