[Hallicrafters] SX-42 I.F. Transformer Questions

[Rich Soennichsen]

Doug,
    It turns out I was chasing the FM portion of the transformer.  It
would make sense that my 455Kc signal would not pass through there.  
The lower section of the transformer is the 455Kc side.  I DO see
output there, though it is attenuated.

This feeds the plate of the AM Detector and is output to an RC filter.
 I will look for a DC change there when I change my signal amplitude.

I still have zero audio out, no hiss, nothing.  So perhaps I can
inject audio frequency here and see where it stops.

Rich



On 2/10/06, Troglodite at aol.com <Troglodite at aol.com> wrote:
>
>
>
> In a message dated 2/10/06 11:51:36 AM Central Standard Time,
> rsoennichsen at gmail.com writes:
> I have my signal generator hooked via a cap to the grid of the first
> IF tube (6SK7) and I see proper amplification and the signal makes it
> to the plate of the second IF.  It does NOT make it through the 3rd IF
> transformer to the plate of the 1st limiter (7H7).
>
> I disconnected one end of the output side of the 3rd IF transformer
> and it ohms out at ~1.4 ohms.
>
> Does anyone know what a typical resistance should be here?  Right now
> I can't think of any other possibilities besides a bad IF transformer
> but I wanted to tap the wisdom here first.
>
>
> I'm not familiar with the specifics of the SX-42, but I have rebuilt a few
> SX-28 IF transformers. Your resistance reading sounds a little low, but I
> have nothing to compare. I'm sure someone has told you already to check the
> capacitors inside the cans? This often turns out to be the problem.
>
> Doug Moore kb9tmy
>