[Milsurplus] DAV IF issues

[J Forster]

First off, this email reflector is NUTS.  It sends out posts in HTML,
but DEMANDS input in plain text. It's a real PITA.  YMMV.


WA5CAB at cs.com wrote:

> Ray,
>
> The DAV-2 Instruction Book that I have a copy of gives a remarkable
> amount of information on the IF transformers.  Unfortunately, some of
> it is clearly incorrect.  But the primary of your Z-101 (Input IF
> Transformer) is definitely bad.  According to the detailed information
> table, the primaries of both transformers are 510 turns of 5-44 S.S.E.
> Litz Wire.  DC resistance given is 30 ohms.  Both secondaries are
> listed as 600 turns of the same wire and DC resistance listed is 26
> ohms.  Which figures don't agree with the turns/wire size of course.

Do you mean that the small number of turns should have the smaller
resistance? Not necessarily so, because the average diameter of the
coils might differ. The resisance is based on the wire length, of course

> Table also gives inductance and AC impedance.  And says the fixed
> padders on the primary and secondary are 45 uufd and 30uufd
> respectively.  There are obvious discrepancies in the inductance
> figures but the impedance figures tend to agree with the stated turns
> counts.
>
> And despite both transformers being said to have the same turns counts
> they have different part numbers.  However, that could simply be
> because they are marked externally by location.
>
> Bottom line is that if you are actually getting 10K ohms across the
> first primary, that's not what it should be, regardless of what the
> correct figure actually is.  I don't know why it doesn't just show as
> open.  [snip]

Maybe a leaky capacitor and open coil? Or a very bad solder joint?

Best,
-John