Clough Brengle 185 B Unimeter

[nsubulysses]

Does anyone know of this brand or would you mind explaining a few things to a young guy? Got this at a flea market for $4 expecting to have to fix it and incredibly it seems to basically work. AC and DC readings are pretty accurate and capacitance readings are as well. Resistance measurements do not work at all, however.




1. What is that weird little 3 prong? Is a battery attachment or is a tube supposed to attach here?

2. Why does it have an AC cord? I plugged this thing into a bulb limiter for my first turn-on because it's so old and the bulb did not light at all. I thought it was dead at first, but actually it works and gives the same readings in AC, DC and capacity whether it's plugged in or not.

3. Resistance readings do not work at all. I would like to fix this if possible. I have not been able to find a schematic or any calibration info. Anyone know of these meters or where to get the info?

4. I found a catalogue from 1941 with the meter in it. It says in "accessories" that a 22.5V C battery is required but not included with the unit. Is this what the 3 prong is for? Is this why resistance measurements do not work?

Here is a link for the catalogue with the 185 B Unimeter in it. It is about 10 pages in and has it's own page. This is the page where it lists the 22.5V C battery that is needed but not provided with the unit when bought new -- http://www.vintageradio.com/history/Clough-Brengle.pdf

[g1]

Sorry I can't help much with this except to say that resistance measurements do require some power source, be it battery or AC to create a DC voltage source.

[nsubulysses]

Hey i do appreciate your reply though, so thank you. that's what I was thinking too.

Apparently the Clough-Brengle factory was somewhere on W 19th St in Chicago. That's kind of cool to me. I am at work right now on W 16th St. I really can't believe this thing is almost 75 years old and still works on 3 out of 4 of it's settings.

[Enzo]

Meters need a battery for resistance readings. I'd wager my lunch money that is your three-prong.


I don't know how it would measure capacitance without battery or AC power, one or the other.

I don't know what teh AC power is used for, I would suspect it was involved in the inductance measurement. Catalog says that happens on the capacity scale. Follow the AC and see where it goes.


This is a basic VOM, and so would measure volts and current and resistance with a battery. The extra features like the AC isolated signal scale (output) are extras.

[nsubulysses]

OK, I re-examined this and I made an error. Capacitance ONLY works when the AC plug is plugged in. AC and DC voltage readings work regardless of if it's plugged in or not.

Also noticed this small print next to resistance. It says "use 90V ext." I am honestly a bit lost since i"ve never used a meter this old. I used my variac to dial in 90V and plugged it into the Ext Battery + and - jacks but still no resistance measurement. Also I guess a battery would be DC and not AC so I'm not surprised this doesn't work.

The AC plug from goes to a transformer. The secondary of the transformer goes to the range switch.

I will measure the voltages and get back. I did last night but don't remember them. Remember one being about 90V though. Gotta run out for food now. Thanks for help so far.