[Elecraft] Sidetone problems with K1

[Jess Gypin]

Hi all,

K1 1408 is alive and running. Almost. There is a problem with the sidetone.
When running through the offset adjustment, tone adjustment, side tone
pitch, and all of the calibrations steps of the K1, it was dandy. Power out
was fine and everything lined up.

Put the speaker in, and the covers on. Set it up on the bench to see if I
could make a QSO.

When tuning the power out and antenna, the side tone was howling. Almost
like it is being re-amplified or there is cross talk or something. I can
hear the side tone under the howling. It sound clean. There is almost a
feedback quality to it. If I adjust the transmit offset via C13 at the back
of the RF board, so there is no offset tone, then the howling stops and I
can hear the normal sideteone. As soon as I try to adjust it so there is an
offset, it howls and feeds back. The howling does track with the AF gain. I
can make it louder and quieter. It is about 5 times louder than the
sidetone.

Any ideas? I have disassembled and and tested with the covers off, on, the
filter board off, screwed down and so on and have not had any luck..

Any thoughts?

Jess AE0CW <><