Eico 950B resistance/capacitance/comparator bridge
 

OK, here's my new toy, an Eico 950B resistance/capacitance/comparator bridge (AKA, capacitor tester) that I recently purchased. It worked when I got it; but, I decided that it needed to be overhauled to insure that it continued to work well. So far, I've replaced all of the non critical paper and electrolytic capacitors. One cap, an 8uf/525V, was replaced with two 22uf/450V caps in series with a 470Kohm resistor across each cap. One of the 1% resistors is out of tolerance and I still need to replace the 3 precision capacitors in the bridge circuit (200pf, .02uf, 2uf). For those caps, I'll use the closest tolerance parts I can get as long as the price is reasonable. Testing the leakage voltage output, I find that the voltage is about 50 volts low and from what I've read, that's a common problem with these and that a resistor in the power supply can be changed to a lower value to get the voltage back up.

Cosmetically, it still had it's protective film over the front panel that was never removed. By now, it had turned an ugly yellowish brown color. I was able to remove most of it with rubbing alcohol and elbow grease. Otherwise, it's in great cosmetic shape.

My main reason for getting this was to be able to check leakage at high voltages; which, is something most modern equipment can't do. As far as testing values, I can do that with my cheap capacitance meter; but, I still want this tester working as best it can.

From date codes, this unit was made in '63; but, it seems that this model was made for many years. The manual that I printed for my unit has a 1954 copyright date on it. On the other end of the spectrum, I read on the Internet that someone purchased one of these new from Radio Shack in '73; so, if that's true, that means this tester was in production for at least close to 20 years. Just out of curiosity, I'd like to know when Eico finally discontinued this model.

http://i538.photobucket.com/albums/f...psf0290416.jpg

I once built a kit of that instrument and, until it was stolen, found it rather useful. Some functions weren't exactly as advertised but for about $20 it was a good value.