Test Gear From the US

[kevin.Hoyland]

Hello David.

Yes i am going to replace the Components that are out and then use it for repair work.
Kind regards.
Kev.
PS i have a Pyramid mk 2 Capacitor Analyzer on its way from the US i wil post photos of it on the Forum when it comes.

[wave solder]

Nice looking bridge but depending on it's design I wonder if running it at 50Hz will affect calibration?

[Yorkie]

I wouldn't have thought so. All bridges work on the same Wheatstone bridge principle - four 'arms' with the test cap in one arm of the bridge in series with the calibrated pot and attached dial, and the meter (or as often as not, a magic eye) across the bridge. When the four arms are brought into balance by rotating the pot, no current flows across the bridge so you get a null at that point on the meter/magic eye, and the value of the cap (or resistor) can be read off the dial. Whatever the mains frequency, it will apply to all arms of the bridge including the cap under test.

At least, that's how it seems to me.

[kevin.Hoyland]

Hello David.
Yes you are right. When i have repaired the other us Analizers i have. I then compaired them with my 2 Hunts capacitor tester i have and the values of the capacitors i am testing are the same on the 110 volts and the 240 volts testers.
Regards Kev

[Yorkie]

I think there's a real irony in Hunts making a cap analyser when just about every duff cap which fails a leakage test was made by Hunts too! But that said, they were a major manufacturers, and the caps have given good service over many decades, far beyond their expected or claimed life-span, so maybe we shouldn't be too harsh on them.

In yet another moment of weakness, nostalgia has triumpherd over commonsense and I recently acquired a Heahtkit C3-U ('U' meaning UK version) Res/Cap bridge which I'm in the process of fettling up. The HT voltages were much lower than the specified +150V and -410V, and apart from the two electrolytic smoothing caps being shot, so was the 'Sentercel' stick rectifier. It was just a series of small discs in a paxolin tube, so I took the discs out and stuffed the tube with a 1N5401 rectifier diode with a series resistor to provide the correct voltages and replaced the two 8uF 500V smoothing caps. I replaced other caps, and I've fiddled about with the resistors in the chain which provides a range of voltages for the leakage test, but I doubt that the voltages were ever that accurate from new. Not important really, as long as caps can be tested at or near their rated working voltage.

The US version uses a valve rectifier and a 1629 magic eye - the UK version uses an EM34, which luckily, is OK, as a replacement would cost me as much as a paid for the C3-U!

I've attached some pics of the Sentercel which might be of interest.

[kevin.Hoyland]

        Hello.

Pyramid CRA2 Capacitor Analyzer From the US.
regards Kev.

[Yorkie]

That looks a stunner Kevin, and in very nice condition too!

[kevin.Hoyland]

Thanks David.
Regards Kev.

[kevin.Hoyland]

        Hello Pyramid CRA-2 and CRA1. Capacitor analyzers.
Regards Kev.

[Yorkie]

I especially like the one with the 'eyelid' over the magic eye. They both look very neatly designed, and pleasing to the eye, as well as functional. Did they come in 'under the radar' from the Staes Kevin, or did you get stung by the Post Office/HMRC, which can truly bump up the cost, on top of the price of the item and cost of P&P.

It amazes me that these beauties aren't snapped up by collectors in the States, and that UK collectors even get a look in. Nice that they both have analogue meters, as well as one having a magic eye.

Thanks for sharing them with us!