Roberts Valve Tester

[Robert Gribnau]

Originally Posted by David Simpson

However, still, the principal of initial circuitry testing for faults & the subsequent testing of the associated valve - without removing the chassis from the cabinet, is a novel one.

Hello David,

Maybe I don't understand you correctly, but many (or even most) of the early valve testers (also called: set tester, set analyzer, etc.) tested the valve while connected in the circuit. See for instance these operating instructions for the Readrite 215 Tube Tester (a simple tester, but there also are many more elaborate valve/set testers with 'in-situ testing' made by Readrite, Triplett, Supreme, etc.).

Greetings,
Robert

[David Simpson]

Hey Robert, thats very interesting. You're the first of all the respondants to highlight an earlier in-situ tester.
I'm guessing that the Triplett 215 was an early(1920's/30's) American tester, probably just for UX4 Triode valves. Which, like the early British B4 valves, had a standard pin/electrode configuration.Hence just the use of one extention plug. If you've got a 215, I'm sure many of us would love to get more details &/or see a picture.
From the late 30's, and certainly the wartime military types, valve testers has a multitude of different valve sockets, from 4 pin up to 9 pin. Therefore the complicated switching arrangements. Its those to which I was refering. I.e. AVO, Hickok, Mullard, Taylor, etc.
If you are a fellow keen valve testing enthusiast, perhaps you could raise a thread on the much earlier makes. Your operating instructions mentions the simple correlation between plate current & grid voltage. So it should be easy enough to plot a Gm graph for ancient UX4 Triodes. An interesting project. I've done it with early 1920's British B4 & Cruciform triode valves.

Regards, David

[Robert Gribnau]

I only own an AVO Two Panel Valve Tester and used an AVO Mk III Valve Tester. But I have built up a vast digital collection on valve testers (pictures, adverts, reviews, schematics, manuals, valve data, etc.) which one day I will publish on an internet page.

A picture and an advert (May 1928) of the Readrite 215 Tube Tester, and a picture, an advert (September 1933) and the manual for the more elaborate Supreme 444 Radio Tester.

Looking at the little information I have on Roberts Valve Testers, I think it dates from (just before) 1947.

[Robert Gribnau]

This is what I have on Roberts Valve Testers.

In the Radio-Craft of April 1947 (page 65) there is an other advert for one: https://worldradiohistory.com/Archiv...ft-1947-04.pdf

[David Simpson]

Many thanks for that extra info. Particularly the Supreme 444. I see it had just 4 valve holders & adaptors, but it looks a great piece of equipment. It's wooden casing looks ideal to hold my V-T 20. I'm not averse to building cabinets & casings(see my CT160 Hybrid picture), but its an awfully long complicated task.
I've had another look at the Denis Tabor article & it in fact mentions a CLEARTRON basic valve/radio tester from the 1920's which is just for B4 valves. Then a later 1930 "Valve & Set Tester" called the SIX - SIXTY, but again just for B4 & B5 valves.
I do hope you can let us see your Digital Collection of Valve Tester information. It would be greatly welcome.

Regards, David

PS. For those interested in V-T's of yesteryear - Denis Tabor's extensive article was in the BVWS BULLETIN of Winter 2001