Simple valve tester.

[Radio Tech]

Hi everyone. Just wondered if anyone has had a go at building the "Simple Valve Tester"? If so how did they wire the valve bases up? So this piece of equipment although using a straight foward cathode follower for the HT. It is the wiring of the valve bases, that is, how to work out how to switch anode, grid 1, grid 2, grid 3, cathode to suit each particular valve, I know this depends on what type of valve is required to test but has anyone done it and how? Ideas please.

Regards

Ken

Glowing Valves Look Good

[ParcGwyn]

Hi Ken,

All I did was wire all the valve sockets up to 9 4mm sockets and then used 4mm plug to plug leads to connect the supply sockets up to the valve sockets. I have republished pictures of the finished tester at:
http://www.instructables.com/id/SImp...e-Tube-Tester/

As I no longer have access to my website. you can see the leads in the photographs.

Regards

Dave
GW7ONS

[Radio Tech]

Hello everyone,

Has anyone had a go a building the simple valve tester (see attached)? I have gone to great length in getting this or its way of supply to function as a valve tester. All the supply voltages like grid bias, ht, and heater volts are there but on inserting a double triode and looking at one half of the triode I cannot get any current to flow in the anode. All of the valve bases I have are wired in parrelell to oneanother and I have fly leads marked from 1 to 9 and hook them up according to valve data and of course set ht, gb, and heater volts according to that data but still no indication of current flow in the ampmeter so what else if anyting can I check or do to get this device to work as it should?

All the best

Ken

[Peter.N.]

I can only suggest that either you have a voltage missing or a wrongly wired connection. Have you checked for the appropriate voltages on the valve under test, i.e + volts on the anode - to zero on the grid? Could be a duff valve of course.

Peter

[Bazz4CQJ]

What valves are you using to try it out with? If the heater lights up, chances are you have the pin connections wrong. Can you try putting a neon in place of the valve to check Ia?

[Vicboduk]

Assuming it is none of Peter’s suggestions, have you checked and calibrated the current meter?
It could be that your shunt maybe too low. As a test; set anode voltage to 100v and connect a 100kΩ resistor between A-K, you should read 1mA.

Vic

[Radio Tech]

Hi Peter, I haven't checked underneath at the valve base, but will try this. The valve is a double triode ecc81; trying it just on one half and will try Vic's suggestion. I have flyleads to the valve bases, the bases are wired for example pin 1 to pin 1 of the next and pin 2 to pin 2 and so on.

best wishes

Ken

[Barrie]

Hi Ken, I have built this tester and added a few extras. To test one half of an ECC81, try as follows. Heater pin 9, Cathode pin 8, Grid pin 7, Anode pin 6, the other heater lead to pin 5.
Second half try Heater pin 9, Anode pin 1, Grid pin 2, Cathode pin 3 and the other heater lead to pin 4.

Please try and let me know how you get on.

Barrie.

[Mike Brett]

Hi all
I do not have enough valves to justify the expense of a full blown valve tester, but
I would be interested in having a go at building this, if someone could tell me what it actually tests for. Also could someone print an amended circuit diagram with the extras included, IE testing for ECC81. Also any pictures that could help in construction.
Cheers Mike

Any chance of the .doc file in a format readble by me?

[Paul Stenning]

I have converted the .doc in post #3 to PDF format.

[Mike Brett]

Before I attempt to build this can some kind soul tell me the following.
What transformer do I need, power rating wise.
What is the diode after the transformer.
What is the power rating of the resistors.
What voltage are the 32u and 4u caps, also the 1u cap.
And what sort of meters are on the A line and K line.
Without this information this is just a none starter for me.
Cheers Mike

[Barrie]

Hi Ken,Have you tried Peters suggestion on voltage readings.On my test i put 150 volts on the anode,0 volts at grid and 6.3 volts on heater,my anode reading is 9mA.If you can let us know your results maybe we can help.
Barrie.

[Ed_Dinning]

Hi Mike, transformer needs to be 250V at about 100mA + 6.3V @1.5A for EL81 (other valves could be used. Valve on test heater winding needs to be suitable for valves being tested so may need to be tapped at 4v, 5v, 6.3 etc. about 2A should be OK here
Diode after transformer could be 1N4007
Caps can be 350/400VW.
Various meters could be used, note that if you use the modules as on Sussex, they need seperate isolated supply voltages for each meter. Standard 1mA moving coil meters can be used with a suitable shunt or multiplier. What have you got?
I haven't worked out the resistor wattage yet.

Good luck, Ed

[Mike Brett]

Hi Ed
Many thanks for the information. I have not got any suitable meters yet but the radio rally season has finally arrived so at least I now know what is required. Resistor wise I would guess 2 to 3 watt or is this overkill.
Mike