The Superior Instruments Co. Model 76 Bridge part 8: Wrapup and final thoughts.

Thursday, March 26, 2026 at 10:41:28

This was an interesting chassis. Not because it’s anything unusual in what it does, but because it definitely shows it was the lower end of the spectrum. Heathkit, Knight, EICO - all of those showed some concern and care in how parts laid in the chassis. This one? Not so much. Things everywhere, parts flying from one side to the other, such a mish-mash of parts and styles and type. I’m still not sure if this one was factory built or kit built, seeing as how it has pop-rivets for everything mounted on the chassis. Seeing as how some of the parts interfere with others, it probably was kit-built.

What do I think about this device?

There wasn’t really anything different about this rebuild except that it required a lot more thought on how to place things, I couldn’t simply move strips around a little or remove parts without drilling them out. That was quite the pain, but it was worked through and eventually everything was re-installed.

I took the opportunity to use some new sleeving I’d purchased, since many of the parts had spacing far longer than anything you could purchase without special dispensation. These parts had a lead j-hooked on, and run to their connection points. I tried to stick with more modern parts like 1% films, good capacitors, and the like - except for the one used in the leakage circuit. This 1.8MΩ @ 2W was hard to find, so I just chose another carbon that was closer to the marked value. It’s not really like it matters, but it is what it is.

I couldn’t get the unit to do much of anything. The eye would close when a part was attached, so something was happening. I’m not sure if the instrument is just that low on the scale, or if the parts I have are bad to the point of being unable to be tested by this device. Regardless, it didn’t seem to do much, and that’s pretty much what I expected. This wasn’t about an accurate instrument, it was about the rebuild process.

That’s all. This is just a footnote shelf queen. Next up is the Simpson 715, finishing up the rectifier section. After that, an EICO VTVM finally gets it’s time on the bench, and perhaps an EICO 950A - assuming I can find schematics for it because that one is a mess. Stay tuned!