An EICO 147A Signal Tracer part 1: Some cleanup and analysis
Thursday, March 5, 2026 at 11:15:36
A few weeks ago, I picked up a couple of EICO 147A signal tracers from a local museum - partly with cash, and partly with trade for some other materials that may be more useful to them. I’m going to be working with the “clean” one.
I’ve already verified this works, and that it doesn’t seem to be doing anything unusual. For this project, it’s going to be a little bit of cleanup and replacing two of the three items inside that could potentially be an issue.
But first, a bit of cabinet cleaning.
These devices had been sitting in a garage for a while, and were dirty both from that and the general accumulation of grime from ages of use. I took the time to wash the cabinet down with some soap and degreaser.
The first item is this molded capacitor. It’s probably paper, but we don’t know.
And, it’s gone.
Surprisingly, it’s still good. This thing must not have seen a lot of use.
I’m going to put a new film cap in it’s place.
A note on this one: This is a part that’s in the wattmeter circuit. It’s unlikely that the wattmeter will ever be used here, but it is in the circuit. The electrolytics should also be replaced here, but they don’t seem to be in terrible condition for the age. That will be a later project.
The new part gets sized for replacement.
Before being soldered in.
The only thing left to do is replace the power cord with a nice new polarized unit. The neutral goes to the wattmeter socket so there’s no live AC when the power switch is off.
Some contact cleaner on the switches, and it all tests out fine. I’m going to pull the knobs and wash them, as well as give it a good panel cleaning before buttoning it up. I’ll see if I can pick up a capacitor replacement wafer at Dayton this year.
The second part of this series will be some quick checks and a final test. Stay tuned!
Next part of this series: Coming soon.