[BC] Te st your wits on this

[Mike McCarthy]

If you haven't already, look at the total broad band emission with a 
spectrum analyzer. Running into a dummy load isn't as frequency 
sensitive as a combiner. It sounds like something out of the primary 
passband is being emitted and reflected back from the combiner. Richard 
Johnson makes a good point about insuring all bypass devices are 
properly re-installed. I would also check neutralization since the 
filament is closely associated with the tube's remaining inner 
operations and possibly return current flow for the plate.

MM

On 2/23/2012 5:04 PM, David Senft wrote:
> Saturday night, Feb. 18th, a BE FM 20T Tx burned up the inner filament
> contact ring. When the ring was replaced, the transmitter ran perfectly into
> the dummy load but would not fire into a Dielectric star-point combiner.