EF50 module

[djrm]

I found this little chassis with a nice red EF50 mounted on it at the sale the other week. I bought it as it reminds me of the old radar indicator unit I used to have which had several EF50s in it. This one looks in fair condirion, I've no idea what it came out of.

       

The other picture shows the covers of a couple of historical documnets, I like the artwork of valve data cover, I hear Brimar name may be being revived. The other booklet is interesting as it contains conversion details for old surplus equipment.

Kind regards, David.

[ppppenguin]

Curious little module. Good quality caps, very ordinary resistors. High quality valveholder. Overall I'd suggest professional rather than domestic.

The Brimar name is certainly being revived. They had a big display at the NVCF earlier this year. https://brimaruk.com/
They are working towards actual valve production in the UK.

[Doodlebug]

That cut out of the EF50 base to clear the base screw doesn't look professional
so I go for a radio ham construction.

I used same high quality EF50 holders when I built my first short wave receiver
70 years ago ! High quality is not the sole preserve of commercial construction

[djrm]

I was curious to see the circuit so I drew it out, very odd.
Perhaps an oscillator or delay of some kind.
   

[pwdrive]

The circuit has some similarity to a basic Fleming-Williams timebase, output taken from the cathode?:

https://archive.org/details/TimeBasesThe...t/page/n43

Lawrence.

[djrm]

Hi Lawrence,
I see you have the very same timebase book I have. I was going to look for myself if there was something similar.
There is no sign of anything other than what I have drawn being connected to the cathode.
There is a cut wire connected to the junction of the 27k and 2k2 resistors which I forgot to draw on the schematic.
I only got as far as checking and seeing that it wasn't a typical Puckle design.
I'm not sure if it should free-run without any trigger.
Perhaps I'll try to fire it up and see if it does anything...
Kind regards, David.