Hi all,

I purchased a Palec ET4a tube tester, and sadly it didn't have any of the original accessories, such as the adaptor for testing CRTs. In the same area as the testing tube sockets are, on top of the unit, there is a small plug socket - for the type of cables used with general test equipment (such as multimeters, PSUs etc.). Is there supposed to be a cable with this? Would it be used to connect to the top cap on valves being tester? I'm trying to test a 1S2 rectifier, but with no results - could this be why?

Also, were there any supplements to the valve parametes booklet? I have a (Printed from online?) copy of the valve parameters, but it is lacking a lot of different types of valves - such as the 6CB6A. Did they produce any supplements with a wider range of tubes?

I know it's possible to still test them using a pin diagram for the tube, but I don't trust my skills enough to attempt that yet.

Thank you,

Chris

I'm not familiar with the Paton, but yes the socket is more than likely to plug in a grid clip. If the 1S2 has its grid connected to the top cap that would be why you can't test it. Most valve tester manuals came with instructions on how to test unlisted valves, the hardest part being how to figure out what the test level should be. The usual process is to use a known good valve of the same type to set a comparison level. Okay if you've got a known good valve, not so easy if you haven't. For a basic emissions tester you only need to know the heater pins and voltage, grid pin and diode pin if applicable. Some valves such as 6AQ5 (I think) had internal connections which would have a special setting.

Most testers came out with regular updates back in the day but they might be hard to find now. I had some success with looking at lists for other testers, you can usually figure out what the settings are for your tester from these with a bit of comparison with valves listed in both.

Wa2ise listed a quick and dirty method of testing batches of valves in this forum somewhere recently.

My Palec ET4A too was missing it accessories when I first got it all those years ago. A top-cap and CRT lead are not too hard to make up. With the CRT lead, you'll need to have a selection of different CRT sockets. The original CRT adapter was plugged into the octal socket on the tester.

To test a 6CB6A, use the same settings as for a 6CB6. The only difference is the 6CB6A has a controlled heater warm-up time of 11 seconds.

Here is a valve socket adapter I built up.