[Heathkit] SB-101 problem

[Ross Stenberg]

Hi Matt, In my case the problem was with the potentiometer used to adjust
the balanced modulator. It was intermittent and caused the carrier to no
longer be nulled.

	73 Ross K9COX 


>>>I have a SB-101 that I am restoring and have run into a strange problem
during the alignment I was going to adjust the idling current and found that
when I keyed the microphone the output of the rig went from 0 to full
output. I traced the problem I think to the double balanced mixer.
It seems to have a carrier output even when there is no audio going to the
mixer. I have replaced the diodes with matched 1N191's and tested all of the
other components in the mixer. I also checked to see that the mode switch
was only grounding on side of the diode ring when in tune and CW.So far I
have had no luck in getting it not to put out a signal when there is no
audio.

>From the circuit description in the manual there should be no output if
there is only the carrier oscillator is that correct?
Has anyone run into this problem or have any ideas?
I appreciate any help.
Thanks,
Matt