Heath Apache Help !!
 

I'm restoring a Heath TX-1 Apache. Everything is working great
except.... on CW there are occassional little frequency jumps up to
about 50 HZ. The frequency always returns quickly to the normal
freq. In a constant key down condition the frequency is very stable.
It only shifts with keying and seem to be worse at higher speeds.

The shift can be heard in a monitoring receiver even in standby mode
when the final is not loading down the power supply. ( and all filters
have been replaced anyway ). I have gone through the VFO cleaning up
bad solder connections and tightening grounds. The VFO tube has been
replaced ( as have the buffer / xtl osc and driver.

Aside from the little jumps, the VFO is extremely stable. I had some
chirp, but it cleared up with the 6AU6 VFO tube replacement.

Any ideas anyone???? Please e-mail to :

73
Bob WB8CAC
http://www.qsl.net/wb8cac

WB8CAC wrote:
I'm restoring a Heath TX-1 Apache. Everything is working great
except.... on CW there are occassional little frequency jumps up to
about 50 HZ. The frequency always returns quickly to the normal
freq. In a constant key down condition the frequency is very stable.
It only shifts with keying and seem to be worse at higher speeds.

The shift can be heard in a monitoring receiver even in standby mode
when the final is not loading down the power supply. ( and all filters
have been replaced anyway ). I have gone through the VFO cleaning up
bad solder connections and tightening grounds. The VFO tube has been
replaced ( as have the buffer / xtl osc and driver.

Aside from the little jumps, the VFO is extremely stable. I had some
chirp, but it cleared up with the 6AU6 VFO tube replacement.

Any ideas anyone???? Please e-mail to :

Looked at ceramic and mica capacitors in the VFO and thereabouts?
There have been some threads recently here and/or on the R-390 list
about capacitors sometimes doing abrupt small changes in value, and
your problem sounds much like that.

--
The Internet is totally out of control, impossible to map accurately, and
being used far beyond its original intentions. So far, so good.
-- Dr. Dobb's Journal May 1993