Remember also, some amplifiers have an interlock switch so you can't run
with cover off. There are ways to handle that, but if you need to know
that, please email privately.
Many ham amplifiers do not have a way to turn on the filament supply
without turning on the HV. Is there a separate filament transformer? Or
is there only one transformer that has both a HV secondary and a
secondary for the filaments (and probably a third secondary for control
systems voltages)? If there is only one transformer in the power supply,
then you will have HV on whenever you have filaments on. In that case
the best way to have the filaments running without any HV on the tubes
is probably to just disconnect the anode (plate) cap leads. You need to
be very careful to keep the leads from contacting anything else (or even
getting close to anything else, this is high voltage). It may be
difficult to accomplish this AND put the cover back on. I recommend NOT
turning the power supply on with the cover off the amplifier. I
recommend AGAINST defeating any interlocks that are intended to prevent
you from turning on the power with the cover off. It may be easier to
completely remove the plate caps and parasitic suppressors, where they
connect to the plate supply RF choke. Then there is no way they could
accidentally make contact with the chassis or other and the cover can be
put on during the degassing burn-in process. Removing the plate caps and
parasitic suppressors will probably only require unsoldering them where
join the plate supply RF choke and the blocking capacitor(s).
DE N6KB
|