[cathoderay57]

Hi folks, testing valves today on my VCM163 I made a switch selection in a sequence I wouldn't normally do. Having tested a valve hot I turned the Function Switch back to "Check(C)" (check cold) and rechecked the leakages by rotating the leakage switch. The heater gave continuity as expected at position h(C) but the cathode position c(C) also showed short circuit. After about 30 seconds the meter needle slowly fell back to zero as though a capacitor was discharging. I have had a look at the circuit and I presume the gradual voltage decay was the discharging of C6. It is clear that in the h(C) position there is continuity from Meter 1+ via S5O, S6B/2, S6A/2, S5B/1, through the valve heater to chassis. However, in the case of the cathode position c(C), the circuit goes from Meter 1+ via S5O, S6B/3, S6A/3, S5A/1 to the valve cathode. Unless the cathode has leakage to heater I cannot see any other path back to chassis. The same condition was repeatable on 3 different valves and yet, testing using the ch(INS) function valves showed all 3 valves to have infinite heater/cathode resistance. Is this a fault condition or am I missing something? Cheers, Jerry