Guys you can’t measure current at tube pins unless you put the meter in series’s with one pin to socket. If you put meter on amps and place leads across large pins you are shunting or shorting the heater circuit. The clicking you hear is the overload relay. Just out meter on Dc voltage. Then put leads on each large pin observe vintage. it needs to be close to tube spec. example a 300 b is 5 volts it will measure very close to 5 volts.
Heater current is determined by dc resistance when tube is hot not cold. if tubes are matched in brand type age it’s ok. if you want to know current use a tube adapter and place one meter lead in tube socket and tge other at tube pin. If negative reading it’s ok or reverse leads to correct. Readings are ok both ways
Heater current is determined by dc resistance when tube is hot not cold. if tubes are matched in brand type age it’s ok. if you want to know current use a tube adapter and place one meter lead in tube socket and tge other at tube pin. If negative reading it’s ok or reverse leads to correct. Readings are ok both ways