Make sure you have the IF's aligned per the manual as the selectivity,
sensitivity, and the slot depend on this. This is the same as with the
HQ170, 145, and 180 that use all or part of the HC-10 circuits.
Dave K4JRB

Mike Knudsen wrote in message
...
I finally got around to working on an HQ-160 I picked up a few years ago.
It
works well, except the CW/SSB is very weak, and the slot (notch) filter
doesn't
work at all.

I expect to check voltages around the 6U8 "linear detector" which I assume
is a
product detector, though how it works is a mystery to me, being just a
pentode
used as a triode. I know the BFO half of the tube is working, since I can
hear
it change pitch with the pitch control on an AM signal.

The slot filter is strictly passive components. I've already played with
the
slug in its coil, and the notch depth control. I just finished working
with my
HQ-180, so I know how effective this slot filter circuit can be -- and my
160
just has nothing. I hope it isn't an open coil.

TIA for any suggestions -- Mike K. AA1UK

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