[Elecraft] Cw warble transmit and receive K2

[Jay Schwisow]

Good evening all,

I have  my K2 (no. 5037) for a number of months and it has been working 
great.  However, after a month of  non-use  I now have a warble  on both CW 
receive and transmit carrier.  I have this on both 40m and 20m and have not 
checked other bands.

 A friend of mine and I have gone through the rig and do not see any obvious 
solder or component problems.

Using a oscilloscope at R30 we found .7v dc and 20 mv peak to peak 80-100hz 
AC.

Could this be a problem with U4 or U5?  Any ideas where I should be looking 
?

Thanks,

Jay - KT5E