02-11-2016, 01:49 PM
(02-11-2016, 09:25 AM)boater sam Wrote: The vhf valve, ECC88, is often low emission due to cathode poisoning, the HT is off when in AM mode.
That's poor design!
To prevent a recurrence, connect a high value resistor - 1MΩ or so - across the switch contacts so that a trickle of anode current continues to flow in the valve(s) in the FM tuner head when operating on AM.
