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Old 24th Dec 2009, 9:57 am   #1
swordholder
Rest in Peace
 
Join Date: Aug 2009
Location: East Preston, Sussex
Posts: 162
Default The "Sussex" Homebrew Valve Tester.

Moderator notes:-

The manual (as of May 2014) is available here:-
https://www.vintage-radio.net/attach.../sussex-v1.zip

This manual supersedes the documents below (however the links remain for reference).

A handbook for this tester can be found here:-
http://g4cnh.com/public/Using_the_Sussex_VT1.pdf

The circuit can be found here:-
https://www.vintage-radio.net/forum/...postcount=1006

Printed circuit boards are available here:-
https://www.vintage-radio.net/forum/...&postcount=926

Transformers are available from forum member Ed Dinning:-
https://www.vintage-radio.net/forum/...&postcount=768

A Bill of Materials can be found here:-
https://www.vintage-radio.net/forum/...&postcount=974

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Hi All,
I have designed and built a valve tester just to prove to myself that I could, also to keep the old grey cells going (I am an OAP).
This is a fairly universal type which cover 6.3v valves on the common B9A, B7G, and octal bases as used in the majority of audio and radio receivers.
Anode and screen voltages are switched DC fed from a pair of current limited FETs, Grid voltage is variable, and is monitored on a panel mounted DVM.
Anode current is displayed on a second DVM. Gm is measured on a third DVM and is measured by reading the voltage on a sensing resistor in the anode. Signal being applied to the grid.
Heater continuity, cathode heater and inter electrode shorts indicated by LEDs on the front panel.
Total cost (apart from the case and mains transformer) I would estimate at around £50 buying new components.
I used DVM modules (bought from China on E Bay at around £6.50 each) as they dont require range switching and are nowadays comparable in price to moving coil meters.
if anyone is interested I can post the circuit etc on the forum.
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Attached Files
File Type: pdf Valve tester2 circuit.pdf (421.4 KB, 11311 views)

Last edited by Paul Stenning; 14th May 2014 at 2:12 pm. Reason: May 2014 manual link added
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