[Hallicrafters] SX-42 problem

[joel hallas]

Robert,

Is it possible that the bandspread is strung so that it operates 
backwards from normal? I have an S-40 A that came to me in exactly that 
condition, and had exactly that symptom. The alignment should occur with 
the bandspread capacitor fully unmeshed to provide the max ratio of Cmax 
to Cmin. Otherwise the high end will be lower in frequency by the amount 
of bandspread in the circuit.

If so, you can complete the alignment by looking at the capicitor, not 
the bandspread dial, and reverse the dial string at your liesure. (In my 
case, it's been 3 years and no liesure, but not so bad with the S-40 
since there's not a calibrated bandspread to worry about <g>!)

GL and 73, Joel W1ZR

Robert Byrnes wrote:

> I have been working on restoring an SX-42 that had been worked on by 
> someone else. I have got it working but I am having a problem with the 
> RF alignment.
> The low end of all of the bands will fall in very close but the high 
> end of all bands is way off. For example, on the BC band 600 khz falls 
> in nicely but at 1500 khz  I will pick up a station transmitting at 
> 1320 khz.
> The high frequency trimmer will adjust the upper end but only about 
> 10% of what is needed. If I move the bandspread off of zero the high 
> end starts to come down. When the bandspread gets to 70 on the dial 
> all bands seem very close at the high end.
> At this point I have stopped.
> I don't know if the problem is a bad componet, an alignment problem of 
> the bandspread assembly, or something the previous owner did.
> I could not find a production run number to use the correct schematic. 
> I was told that it was stamped "inside the chassis" but I did not find 
> it.
> I would appreciate any comments or information.
> Bob ke6mtt
>
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