VINTAGE HUNTS CAPACITOR AND RESISTANCE ANALYSER CB3

[djrm]

Seen today on ebay, I wonder if it has a self test function ;-)

[Mike Watterson]

No. it hasn't

  CRB3manualV2-2022.pdf (Size: 965.94 KB / Downloads: 14)

Nor has my equivalent, which was €5 at a local Amateur Radio Rally and easy to restore.

   
I've not used it in maybe 12 years

  CR50 C-R bridge Issue 1.pdf (Size: 125.46 KB / Downloads: 8)
   
   

I use a ex-camera built-in flash in a small Eddystone style box with neon and two terminals and spring loaded power switch to measure leakage.
A kit meter for from 0.5pf and tiny VHF coils. Uses a precision (0.5% marked) Silver mica cap selected on test with modern lab grade bridge as self test internal reference.

A Chinese tester that mostly does from 100pF, 100uH, diodes, resistors, transistors, FETs etc and shows pinout.
DMM with RS232 (serial never used now).
A cap / coil tester able to measure large caps and Henries

[Mike Watterson]

Likely the caps in the Hunts are better than the ones they sold radio manufacturers.

[djrm]

Likely the caps in the Hunts are better than the ones they sold radio manufacturers.

That was my point, Mike. Rather expensive but looks handy. I have some old diy books showing how to make this kind of bridge though never built one myself. I do have an old GPO line testing bridge used to determine cable fault distances. This was before the ones with a CRT became popular. 

It's a good idea to make a leakage tester though. I have some suitable supplies including an old flash gun. My old russian multimeter needed an external high voltage supply for its high ohms range. I still have that actually it is a small toroidal transformer with some transistors driving it.
D

[Ed_Dinning]

Hi, these bridges are quite easy to build and good quality 1% silver mica caps are easily obtainable, no reason not to make one considering the prices of things like the CRB.
Will work OK with a 50Hz supply but much better at higher frequencies

Ed

[Mike Watterson]

But my cheap Kit (predated the current Chinese testers) with a PIC and two line LCD text display has a relay and only one precision cap to self calibrate.
The calibration will zero current open circuit jig for caps or in Inductance mode a short circuit jig.
Does much smaller values and more accuracy than the current multitesters. Sadly the developer is dead. He also did the AADE Filter Design CAE for Windows (XP at the time), which sort of runs on WINE.

http://web.archive.org/web/2006071806422....aade.com/
L/C Meter IIB
Inductance/Capacitance
Meter.

.001uHy / .01pf resolution
Automatic Ranging
Self Calibrating

So better than my earlier post suggests. I built mine into a case from a battery pack of an old laptop.

The CAE program is good and the Wayback Machine download works (last capture 2015):
http://web.archive.org/web/2015052207014...nstall.exe

[Mike Watterson]

The cheap Chinese R L C semiconductor testers are much easier to use than a bridge and are good enough for most people. They will give the wrong answer on a leaky or dried out electrolytic and won't see problems with leaky paper caps. A Low voltage current limited PSU for electrolytics and a several microamps limited 400V approx leakage tester for any other cap is needed before checking value. Mostly only some USA vintage silver mica will fail on value. All other caps typically fail on ESR/Dried out or leakage for electrolytic, or breakdown leakage on paper.

[Bushbaby]

Ive got a Hunt CBR3 that I got hold of by chance many years ago for virtually nothing. Its not in great condition especially the outside casing. I'm concerned that trying to clean it up at some point in the near future, I will lose all of the printed scale labelling. Is there any chance at all that anyone has a good front pic/photo to scale so that I could potentially use this if the printed labelling could be completely lost in cleaning up?

[Bushbaby]

As I indicated, not in a great condition.

   

[Mike Watterson]

Take knobs off
photo with ruler
Edit on PC. Use ruler to scale. (Inkscape or the GIMP).
Mirror it and laser print on baking paper/greaseproof paper/ glossy stock (not any inkjet media).
You then can iron that on with a hot dry clothing iron
Soak paper till it completely disintegrates.
You can also get sheets of waterslide "paper" for laser (avoid stuff sold for inkjet).

Black is easy. White is challenging, but I managed it by printing on laser rated clear film and then white thermal transfer film. Doesn't work well with waterslide. The clear polyester isn't obvious behind the glass. A broken glass scale. Cost me €5 for a new glass blank and €5 each for the two holes they cut for the knobs.

So your task is easier. Some people have used the iron on technique for PCB resist. I found it works well on cloth with colour laser, but only bold yellow, cyan, magenta, black areas as colour laser prints are done in C Y M K layers which are reversed by the iron on method and fine dots for shades don't work.