[Hallicrafters] S-120 Tuning Questions
Wj5mh at aol.com
Wj5mh at aol.com
Sun Jan 2 14:51:24 EST 2005
A month ago I purchased an S-120 at a garage sale, and I just finished
refurbishing it. However, I seem to have a problem with tuning actually matching
the dial scale ON ALL BANDS. Even after an alignment.
This may be a clue. I noticed that the dial pointer would not fully move to
the left end of the dial (under the zero of the band-spread marking) when
the tuning cap was set to max capacitance. I managed to release the tabs,
remove the glue and slide the pointer to the left. Now, the pointer moves from
one end of the dial to the other, matching min and max settings of the tuning
capacitor.
I carefully followed the alignment procedure starting with the broadcast
band, but was unable to get the dial to match after working with the trimmer cap
and inductance settings numerous times. Example: 1300 kHz at 1300 kHz, but
590 kHz on the low end would be 560 kHz.
Working with the other bands generated about the same results. Example of
band 3: 10 MHz would be OK, but 5 MHz would show as 4.7 MHz. 40 meters would
actually show up as 6.7 MHz.
I was thinking that the dial string could be causing the problem, because of
some string diameter to cap rotation ratio, but the string looks original.
(It's small diameter and white. Band-spread is larger diameter and black.)
Whatever it is, it's affecting all bands. I know it's a cheap set, but one
would expect to dial to be a little closer than it is. If you've worked on
one, what's been your experience?
I'm using high-side injection for all bands. To receive a station at 11
MHz, the oscil is set to 11.455 MHz. (I don't even know if this is correct
since I started from scratch with the alignment after trying to touch up the
alignment the first time.) Oscillator signal sounds clean on an external
receiver. The S-120 seems to receive fine.
Thanks,
Joe
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