[cathoderay57]

I'm bumping this to add a request. I am still finding that the cathode shows a short circuit in c(C) leakage position) BUT only immediately after the valve has been heated - any valve will give the same result and therefore either it is a feature or a fault on the VCM163. The only explanation that I can think of is that while the heater retains residual heat, and after the heater power has been removed, maybe there is diode action between the inner heater wires and the cathode causing conduction in the c(C) test position? This would be consistent with the symptom because the short circuit reading decays as the valve cools. Please would another member owning a VCM163 run the same test outlined in Post #1 and let me know if they get the same result? Thanks, Jerry