[Hammarlund] Unstable Oscillator adjustments in the HQ-180

[w5jo at brightok.net]

What is the condition of the bandswitch contacts.  Had a similar problem 
with a National and cleaning them with denatured alcohol  fixed my problem. 
Other than that, I am beginning to think the mica capacitors located in the 
bottom of the cans are the problem which will require removal and 
replacement.  Usually the capacitor problem will be one or two of the cans 
not all of them, so what, beside the bandswitch, is common to the oscillator 
section.  I believe someone mentioned the oscillator tube.

73,

Jim
W5JO

-----Original Message----- 

OK, as far as I can determine the slugs and caps are in good shape. The
touchy issue means that when I put the adjusting tool on the screw and just
tweek it a little the output jumps.  On all of the IF transformers, I can
turn the adjustment slowly and see the output drop or increase relatively
slowly so that I can sweep through the peak and back up to find it then
remove the tool and have it stay put.  with the oscillator transformers even
a slight turn causes a sharp change in output and it is almost impossible to
stop on a peak. Sometimes just removing the tool shifts the output peak...
The "problem" exist on all of the HF Osc transformers so it is something
common to all band switch positions. All the tube socket voltages and
resistances are nominal ( ±10% maybe ). I have the set working fairly well
but can't help but think that it could be better...  I've been using it for
the Classic Exchange so after Tuesday I will put it back on the bench and
continue trouble shooting.... I was hoping someone had experienced the
symptom before and could report their findings...

TNX  es 73
Ron K3PID