[Hammarlund] HQ180 main tuning

[Rodger]

Mike,

Welcome back to the cold state of Illinois!

If the plates are actually touching you will probably hear some 
crackling noise as you tune.  The symptom you describe sounds more like 
poor contact between the wipers and the rotor and I would first try 
cleaning with contact cleaner before going further.

If this isn't the problem and it does appear to be a plate issue then 
before bending any of the plates first check rotor centering.  To check, 
tune to the low frequency end of the band so that the cap is fully 
meshed and look straight down from above to avoid parallax error.  The 
rotor plates (those that have not been bent or "knifed" to improve 
tracking) should be centered between the stator plates and if they are 
not then you will need to carefully adjust the thrust bearing (located 
at the far end of the capacitor) to recenter the plates.  If the rotor 
is centered and some of the plates are scraping then a small pick, very 
carefully wielded, should work to straighten the plates.  You will need 
to re-align after either centering the rotor and/or bending plates.

Rodger WQ9E

judyt732 at sbcglobal.net wrote:
> Hi all..I've returned to Illinois after a six year hiatus in Florida. 
> My HQ180 has sat on a shelf in a heated/air conditioned home while I 
> was away. I turned it on last night and it works, although it needs 
> some alignment after being moved by others a couple of times. The main 
> tuning "jumps" on the three highest bands through the middle portion 
> of the tuning range. Rocking the main
> tuning knob back and forth causes a station to jump up and down two to 
> three KHZ's, making tuning in a station very difficult. (I have to use 
> the bandspread.) No mounting or cold solder problems with the main 
> tuning capacitor assembly. However it looks like one or two of the 
> variable plates might be dragging against the fixed plates. This is in 
> the section closet to the front panel. Anyone know of a tool or any 
> tricks to straighten the plates?  Thanks, 73's...Mike
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