[Collins] audio feedback problems with kwm-2a

[Fern]

     I've been driving myself up the wall with a kwm-2 round emblem
 production around 1969 which has an issue with slow drop off of ptt and 
also
 getting audio feedback when releasing ptt. All tubes have been checked ok
 with tube checker plus did swap of them by robbing tubes one at a time from
my other kwm-2. I've tightened all of the screws re the tube sockets with no
 difference. The diode in the screen of the finals is ok and the R122 47K is
 in place going to the cathode of V3. The positive bias on the cathode is
 between 6 and 8 volts depending if on receive or transmit.
   Any suggestions as to how to tame this problem would be greatly
 appreciated.     73 from Fern