[Drake] Strange problem with T4XC

[DJED1 at aol.com]

I was starting to operate this morning on SSB when I glanced over and saw 
that the plate meter was almost pegged without any voice input.   I shut it down, 
and investigated-   When I first turn the T4XC on, the plate current will be 
at zero, then will go to 450 ma if I turn the switch to tune, even though  the 
RF gain is all the way down, and it won't go back down if I turn the mode 
switch back to SSB.   Even stranger, I substituted my other T4XC and it did the 
same thing (I just checked out both last week, and they worked fine!).   So I 
was sure I lost the bias or screen voltage and pulled the AC4.   The bias 
voltage was OK, but both the HV and LV were very high.   Part of this may be due to 
high line voltage (124V), but the HV was around 750 V, and the LV around 340 
V.   I tried feeding the AC4 with a variac to pull down the voltages, but the 
strange behavior of the plate current persists.   Anyone have some ideas as to 
what is wrong?   This one has me stumped.
Ed   WB2LHI