An EICO 950A R-C Bridge Part 6: The last components are placed.
Friday, June 26, 2026 at 06:52:49
This has been a long journey of removing and replacing things in this unit. When I started, it was “can I actually do this?” But, it’s been done. All of the components, save the transformer and the pots, have been replaced with new. All resistors are now 1% film, all capacitors are now new electrolytics or modern film parts. I even have some new tubes for the unit, as the eye was weak and the 6X5 was baked.
This part was finishing up the power supply, and running lines and parts for the eye tube circuit, as well as adding a terminal strip for the line cord. I had planned on adding a terminal strip on the power supply side, mostly because the OEM build had everything jammed onto that one little strip and the tube socket, and I wanted to lay out the parts in an easier to see manner. I used a long strip, and it turned out decently.
I was going to put the AC line on this strip as well, but decided to move it nearer the switch, so there’s not AC running all over the place. I used a single position w/ground strip for that, and all of the incoming AC is now close to itself.
The only issue I ran into here was R7, which runs from a potentiometer on the face to the negative side of the power supply. I can swear up and down that I ordered the part - a 30k resistor - but these were not in my stock. I either ordered them and “put them away,” or I didn’t order them. No idea which. To fix that, I took some comically over-spec’d resistors and made a 30k unit. So…there’s two 15kΩ, 15ppm, 0.1% resistors making this part up. That outstrips pretty much anything I’ve worked on to date!
Here’s the photos:
The next step is to check the wiring, re-install the eye tube mount, and then turn it on! Stay tuned!
Next part of this series: Coming soon.
Previous part of this series: https://wereboar.com … -5-the-power-supply/
Wrapup and final thoughts: Coming soon.
References
YouTube playlist for the EICO 950A Rework: https://www.youtube. … XCviSJjIoCDM&pp=sAgC
Schematic: Coming soon.