[Kenwood] Capacitor reliability

[Ken Brown]

I maintain an autocorrelator spectrometer at a radio telescope. The RF
and analog portions are powered by linear mode regulated power supplies.
The power supplies are pretty typical designs. Transformer, full wave
bridge rectifier, capacitor filter, followed by the regulation
circuitry. The power supplies are Acopian  brand and the big
electrolytic filter capacitors after the diode bridge are "BG" brand.
There are four 3.3 Volt 30 Ampere supplies which have all failed due to
these electrolytic capacitors failing. A few of the other voltage power
power supplies have also failed in the same way.

Acopian has a real good warranty and good service, so they have repaired
them a few times at no cost to the observatory, other than the shipping
cost. They replace the bad "BG" electrolytics with new ones, which then
fail again in about six months. This failure rate may be worse than
typical, because of the low atmospheric pressure and humidity at nearly
14,000 foot elevation. I imagine that the electrolyte evaporates more
quickly in that environment. These Acopian power supplies have not had a
single failure other than the "BG" electrolytic capacitor failure.

It is more cost effective for me to change the capacitors myself than to
have Acopian do it under warranty. The purchase and shipping cost of
new, better quality, capacitors is lower than the round trip shipping to
Acopian. I have been using Mallory brand electrolytic capacitors in
place of the "BG"s and not a single one has failed since I started using
them about three years ago. Failure of all of the "BG" capacitors seemed
inevitable, so they have all been replaced with Mallorys.

I have never determined exactly where the "BG" capacitors are made. I
suspect Asia.

DE N6KB