[Drake] TR4C weird xmit trouble

[N4ch at aol.com]

Sounds like a parasitic oscillation (possibly in the TR-4C's  PA) to me.   
Check neutralization.   If that doesn't fix  things, something like a bad 
bypass cap or other defective component, bad solder  joint, or other fault may 
be causing an unwanted feedback path somewhere,  possibly involving another 
stage, and not just the PA by  itself.   If U can borrow a spectrum 
analyzer from someone, try  connecting a couple feet of wire to its input, and let 
it run within a few feet  of the radio chassis so that U can loosely "see" 
what the radio might be  spraying out, and see what's going on.   DO NOT 
connect the analyzer  to the transceiver directly, as U will fry it.   If U can 
find a 40-50  dB power attenuator pad, then U could run the output of the 
TR-4C thru that into  the analyzer, though.   Set the sweep on the analyzer to 
cover from as  low in frequency as it goes all the way up to 30-50 MHz or 
so.   Bet  you will see some ragged RF on a different frequency than what the 
 transceiver is tuned to.   It might be that an earlier stage is flying  on 
some frequency removed from what the PA is tuned to, and this could explain 
 the high plate current.   Good luck and 73, Herman,  N4CH.