Cw warble transmit and receive K2

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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

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RE: Cw warble transmit and receive K2

Don Wilhelm-3
Jay,

I do not believe it is a problem with U4 or U5 - but a problem with the VCO
range.  0.7 volts at R30 is too low and the VCO is likely unstable as a
result.  Adjust L30 to bring it back up and check the low and high ends of
each band to see if they can be between 1.5 and 7.0 volts at the left end of
R30 (with the K60XV option installed the range is 1.0 to 7.5 volts).

If you once had it adjusted properly and now it has changed, look for
something that has changed the values of the capacitors and varactors in the
VFO Range Select area.

73,
Don W3FPR

> -----Original Message-----
>
> 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
> ?
>

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Elecraft web page: http://www.elecraft.com