RadioBanter - View Single Post - Hallicrafters S-20R alignment

March 20th 06, 02:53 PM posted to rec.radio.amateur.boatanchors

On 3/19/06 9:03 PM, in article
, "Skyrider"
wrote:

I am having a problem aligning an S 20R. The receiver has just been
re-capped, however the problem I have been having was present before
the set was touched. (The set just has much better sensitivity and the
transformer runs cooler now). The problem I have been having is this:
When I try to align on band 3 (the only band which gives problems) the
closest I can bring it to proper alignment puts 7 Mhz at around 7.5 or
so on the dial, and 10 MHz at about 12 Mhz on the dial. I cannot bring
the dial tracking any closer than this. The other bands seem OK. I
have checked the wiring against a parts receiver and do not see any
problems. I verified that the oscillator is 455kHz above the received
frequency by checking a known working S 20R (which I have owned for 36
years). There does not appear to be any problem with the
trimmer/padder caps or the coil.

Any ideas???

I'm not familiar with that receiver, but I have a general suggestion.

Be sure you are adjusting the trimmer cap and coil slug at the correct ends
of the dial. On any band, the designer might use either the sum or
difference frequencies out of the mixer, which may call for tweaking the
trimmer (hi freq end of the loc osc) to set the low freq end of the dial,
etc.

Don