08-06-2017, 10:40 AM
Hi.
The fact that you got the heaters to light with 6.5v and nothing with the valve in place tells me the base is either shot or wrongly wired assuming you definitely have voltage at the heater pins of the valve. AC or DC fed to heater is irrelevant, don't forget your theory!!!
Also running heaters only would take years to cause cathode poisoning and that's if you believe in it in the first place. Testing conduction on a hot valve with a multimeter doesn't always work, especially those with a 1.5 volt battery
The fact that you got the heaters to light with 6.5v and nothing with the valve in place tells me the base is either shot or wrongly wired assuming you definitely have voltage at the heater pins of the valve. AC or DC fed to heater is irrelevant, don't forget your theory!!!
Also running heaters only would take years to cause cathode poisoning and that's if you believe in it in the first place. Testing conduction on a hot valve with a multimeter doesn't always work, especially those with a 1.5 volt battery
