Shaun Merrigan's Information Pages


Tag: RIFA Safety Capacitor Failures


RIFA Safety Capacitor Replacement in HP Gear

Posted by Shaun Merrigan in Electronics, Restoration, Test Equipment. Comments Off on RIFA Safety Capacitor Replacement in HP Gear

3rd January

In a previous post, I had documented the condition of several RIFA Y Safety capacitors, showing clearly the cracked condition of the outer case. This condition is a precursor to the well documented failure of this style of RIFA capacitor. Reportedly, these problems have been solved since Kemet squired RIFA in 2007. Of course the equipment which contains these potentially failing capacitors is typically older than 2007.

For example, I recently replaced six (two from each instrument) of these capacitors from the following equipment:

HP 3245A (1992)HP3245A (1992)HP 3458A (1989)

HP 3245A (1992) Original RIFA Safety Capacitors. The line filter is on the bottom right.

HP 3458A (1989) Original RIFA Safety Capacitors. The line filter cutout is on the bottom right.

Each and every RIFA Safety Capacitor I removed from this equipment showed cracks in the case.

Cracked RIFA … Read More »


RIFA Safety Capacitor Failures

Posted by Shaun Merrigan in Electronics, Restoration, Test Equipment. Comments Off on RIFA Safety Capacitor Failures

13th November

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 general consensus is that the capacitors fail because the outer case (presumed to be a type of epoxy) develops cracks which allows moisture to penetrate into 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 … Read More »