I found what looked like a liquidation of a commercial electronics lab on eBay a little while ago. I picked up two resistance decade boxes and a Systron Donner counter with Nixie display all for about €50. I thought some people might like to see some pictures as the resistance boxes are a little different from what I've seen in the past.
I was surprised when these were delivered, they are much larger and heavier than I was expecting. I can't find a production date but the stamped steel and Bakelite(?) controls suggest 1960s era. Both unit were covered in grime.
"Patented Dual Dial Non-Reactive Resistance 0.1% Grade". The 0.1% grade is what caught my eye, but the "dual dial" system is interesting. Essentially, when a decade is switched to the end of it's travel the switch can be rotated further to access a separate decade. The hundreds of ohms range can be switched to a hundred
ths range for example.
Opening up the case I realized why it was so large. All the switches are huge over-sized assemblies that look like they are machined from brass.
The switches are soldered together with bent strips of copper, there are no wires.
The resistors are custom wirewound around a shared form for each decade.
I did notice this capacitor connected across one resistor , I'm not sure why. It's marked 23pF.
After taking a look at the inside's I removed all the knobs and dials and cleaned up the front panel and case with some window cleaner. There is still a little bit of sticker residue left but I'll take that off with IPA later.
It seems to work well. I can dial in resistances form 0-10k in steps of 1 ohm. There seems to be slight settling time on the measurements but I'm using a slow meter (Extech 330). I might test this again with a Fluke 87 to confirm the values change as soon as the switch contacts move. It's hard to say how well the small ranges of 1mOhm to 0.1Ohm work, as this is right down below what the meter I had at hand can measure.
The other unit I have is similar - three dials covering a 1k-100k range with lower ranges of 0.1 to 100 ohms. I'm pretty happy with these, a little awkward to use but a bargain.