I have found myself a valve RLC tester/bridge
It is quite obviously a kit built by someone.
I've searched through the Radio & Hobbies/EA index and came up with some possibilities, but not an exact match.
The photo is here ---> http://i204.photobucket.com/albums/bb202/....jpg.

The top terminals are not 'period correct'
It uses the following three valves. 84/6Z4 as the rectifier. 6U8 and the eye is Vi103

The articles that reference R&C bridges are;
R&H Dec 1948 - Doesn't match
R&H Dec 1954 - Closer but still not correct
EA May 1966 - Transistor version
EA April 1968 - Listed as RC bridge. Does anyone have this article?
EA Nov 1972 - Convert RC Bridge to measure L. Does anyone have this article?
EA March 1974 - Transistor version
EA March 1978 - RLC Bridge. Does anyone have this article? (Most likely uses transistors)

I have started tracing the circuit as I can't get it to function. The valves all test OK, all the caps & resistors have been checked/replaced where needed. I suspect an assembly error somewhere.

The difference from the first two articles is mine has a value/tolerance switch and a bridge gain control.

Has anyone got any idea???


Ben

It would be a fairly safe assumption that any EA circuit post 1966 will use transistors, that just leaves the two R&H articles as a reference.
Your unit looks very similar to the Dec 1954 R&H unit so it may be the basis on which it was constructed. It is quite possible that whoever built the unit made the modifications as well. That's the trouble with home made gear, it doesn't have to follow an established circuit.

Face looks similar in style to my 1938 VCT VI 103 is a British Mil. number pre 1941

Oscillator may not work without a test capacitor if it uses one as it is possible to use mains frequency.

There are plenty of circuits around and it may be common or we will possibly see the error from the drawing.