[Hammarlund] Oscillation in HQ 180A

[John King]

Nee benefit of your knowledge, experience and
expertise on the HQ 180A.

I have a beautiful HQ 180A that has an oscillation in
certain knob settings.

1. The oscillation only occurs when sideband selection
knob is in the LSB position. It will not occur in the
USB or BOTH positions.

AND WHEN

2.The BFO is turned on.

AND WHEN

3.When the AVC is in either the SLOW and MEDIUM
positions. The oscillation will not occur with the AVC
OFF or in the FAST positions.

When the above settings are made, the oscillation
occurs and appears to be sensitive to the setting of
the RF gain control. The AF gain control only affects
the volume of the oscillation and seems to play no
part in the start of the osxillation.

Seems that a bad component might be the cause when the
component is switched in by the combination of
settings stated above. Probably a capacitor is the
culprit but before I remove the old gal from her case,
I would like your ideas.

Otherwise she is a beautiful specimen with the
external crystal deck and inside crystal deck for
crystal control. It is difficult to tell what model an
HQ 180 is because they used the same general manual
and nomenclture for the receiver regardless of
changes.

Your expert assistance in this "fox hunt" will be
greatly appreciated. Thanks and 73, John, K5PGW


		
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