[Hammarlund] HQ-170a intermittent RX problem on certainbands<100kc calibrator>

[Kim Herron]

Hi Mike!

     An HQ-170 when properly working should show between 40 to 60 over 9 on
the S-meter with the calibrator signal on 160 meters.  They don't leave my
shop unless they are there.  On 10 meters you should have S6 to S9 depending
on where in the band you are.  On 6 meters you will get an audio indication
with no S meter movement to an S2, depending on where you are in the band.
If you have one band that is working well, your oscillator tube is PROBABLY
not the fault.  6C4's are a known issue, but usually what you have is a tube
that will work in part of the band, and then the band goes dead when tuned
up or down.  A Tung-Sol or RCA or the best choice to use in this circuit.
Your 15 meter band should be working if 10 is.  I'd guess that your antenna
coil or RF coil is open on the 15 meter band. You can check that with your
ohmmeter.  I'd also guess, from the descriptions that you're providing that
this thing has set for a long time and is way out of alignment.  That would
account for your extremes on signal strength.  The RF/IF cans in these
receivers are sensitive to moisture and when they absorb moisture, they go
way off in adjustment.  If this thing isn't somewhere warm and relatively
dry as far a humidity is concerned, then do that.  Fire the thing up and
just let it run for several days to drive the moisture out and then see what
the rest of the bands sound like and how they work.  Often, they will come
back to life on their own.  You'll still have to deal with the 15 meter band
issue.  Again, look at your front end coils for the 15 meter band.  One of
them is very likely open so your not passing signal. 


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