Valve testers & 'soak' testing.

[trobbins]

Originally Posted by woodchips

Leakage at PIV, valve hot or cold?

I did actually test that out - there can be a difference - so likely depends on cause.

Originally Posted by woodchips

If DC then is it polarity specific?

I did actually test that out - there can be a difference - so likely depends on cause.

Originally Posted by woodchips

Leakage similar between anodes?

I did actually test that out - there can be a difference - so likely depends on cause.

Originally Posted by woodchips

Why should it leak? Glass is a good insulator, does it leak between any two pins, connected or not?

The causes could include gas and metal deposition on mica. I did a summary of the results in section 7 of linked doc: https://www.dalmura.com.au/static/Po...ube%20amps.pdf

Originally Posted by woodchips

Emission imbalance, normally the cathode has more than enough coating to supply the number of electrons, so would this be an indication that the valve is near end of life?

The 5U4 I tested are directly heated cathode, so likely some difference to say a GZ3x, although worth reading the linked forum (Figure 33 hyperlink) as nevetslab was measuring anode currents in 5AR4.