[Milsurplus] DAV IF issues

[J Forster]

WA5CAB at cs.com wrote:

> Well, that's true.  If the primary is wound over the secondary, that
> could account for it.  But that won't work with double-slug tuned
> coils.  But other transformers of the era that I've seen all have the
> same coil ID (slug container tube is straight cylinder).  But it's an
> anomaly that will be settled upon inspection, I guess.

That's not what I meant. If the two coils are pie (pye?) wound, the
aspect ratio of the coils could be different, hence the different R's
due to the different average turn length. I've never seen inside one.

> And I considered the possibility that 4 of the 5 strands were broken
> but that would only jump the resistance up to about 150 ohms.  A bad
> solder joint is certainly a good possibility, though.

Even having all but one strand bad is likely insufficient. I was
thinking more like a corroded joint or flux joint. IMO, the two-point
failure of an open coil and leaky cap is more likely though.

Best,
-John

>
>
> In a message dated 9/10/2007 11:22:44 AM Central Daylight Time,
> jfor at quik.com writes:
>
>> 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
>>
>
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