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.
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: https://wereboar.com … -removed-components/
Previous part of this series: https://wereboar.com … -5-the-power-supply/
Wrapup and final thoughts: https://wereboar.com … -and-final-thoughts/
References
YouTube playlist for the EICO 950A Rework: https://www.youtube. … XCviSJjIoCDM&pp=sAgC
Schematic: https://wereboar.com … %20Schematic.jpg.zip
Magic Eye Test (short): https://www.youtube. … m/shorts/hYwHlrx1nR8