[Drake] T4XB dirty CW signal on 20 meters

[DJED1 at aol.com]

If its clean on the other bands it kinda eliminates most of the circuitry,  
like the filter caps and the PTO.  You could also try it in transceive  driven 
by the receiver to see if its OK that way.  If so, all evidence  points to the 
crystal osc in the transmitter.  I had a 20M crystal die in  my T4XC, so they 
do go bad at this age.  I swapped another crystal in to  verify that it was 
the problem.  You could swap in the receiver's crystal  to verify that its the 
problem.  Good luck with your troubleshooting.
Ed