Christy Electronic Tester

This compact tester made by Christy Electronics can perform a variety of electrical tests. In particular, it can perform the same "dim bulb" test when starting up an electrical device as the home-made tester described on my Dim Bulb Tester page.

I was first made aware of this tester in an email from Gerry Bertrand, who generously provided photos, scans, and a schematic diagram for this article.

About one year after Gerry contacted me, I ran across one of these at a second-hand store. The $15 price was reasonable, so I picked it up. Here is a photo of my unit as found.

The next three photos show Gerry's unit after disassembly and restoration.

The next photo shows the innards of my tester. As you can see, it was a pretty simple kit to assemble. The builder only needed to connect wires between the various controls and indicators shown on the tester's front panel. Except, that is, for a small selenium rectifier and an 8-mfd electrolytic capacitor.

As you can see from the above photo, the little red rectifier fell apart at some moment during its service life, and dropped all but one of its plates. I found them rattling around the bottom of the case when I opened it up. In the storage compartment of the cabinet was an unused replacement rectifier, which you can see to the left in this photo. I guess the previous owner intended to repair the tester, but never got around to it.

Selenium rectifiers are unreliable and potentially dangerous, so I'll replace the old one with a modern silicon diode rather than take my chances on the spare selenium unit, even though it appears unused. Inside the cabinet near the rectifier location is a big black burned spot, indicating that it gave off a lot of heat when it failed! A type 1N4005 diode costs about $1 and should be more than adequate.

The same goes for the electrolytic capacitor. Even if it hadn't been used all these years, the capacitor probably has dried out and become unreliable, if it works at all.

Gerry traced the circuit and created a schematic diagram for the Christy, for anyone who wishes to build a similar tester. Click on the image below to view the schematic.

This tester was apparently sold as a kit. If you find one, you might want to carefully check the connections against the schematic, to ensure that everything was wired correctly and that the builder did not leave any cold solder joints, etc.

Below are links to the Christy manual, which includes operating instructions as well as building instructions. The final link contains a sketch with specifications for building a carrying case just like the original, should you wish to do so.

Page 1   Page 2   Page 3   Page 4   Page 5   Page 6   Case

An advantage of this tester over my home-made dim-bulb unit is that it includes an ammeter to show the power consumption of the unit under test. If you're an enterprising builder, you could follow the schematic and manual instructions to make one of these for yourself. Or, if you run across one at a flea market, this page will help you learn how to restore and use it.

Enjoy!