[AMRadio] Need help identifying National part


BILL GUYGER bguyger at sbcglobal.net
Fri Dec 26 18:19:19 EST 2008


Just for what it's worth, I agree that it seems to be an audio transformer of some variety, and you can BALLPARK the impedances by measuring the DC Resistance and multiplying by 10. Ohm out the coils and see if there are center taps. With 5 leads, it sounds like one coil has a tap. Whether or not it's in the center will be revealed by the VOM. 

Then too, it may be an inductor with multiple taps on one coil. Mr. Ohm's  little meter will reveal all.

Bill AD5OL



----- Original Message ----
From: EP Swynar <gswynar at durham.net>
To: k5pgw at yahoo.com; Discussion of AM Radio in the Amateur Service <amradio at mailman.qth.net>
Sent: Friday, December 26, 2008 11:49:42 AM
Subject: Re: [AMRadio] Need help identifying National part

Hi John,

I checked my Radio Parts Master catalogue for 1964, as well as the catalogue
sections of the 1948 & 1940 ARRL RADIO AMATEUR'S HANDBOOK --- nothing, nil,
zilch, nada...

I wonder if that part number is really a National number, per se...? Perhaps
it's the part number of the MANUFACTURER who originally purchased the part
for his OEM application...

Hammond Manufacturing did the same thing with their transformers: they were
custom made on occasion for a specific end user in quantity, with a unique
part number affixed to the transformer that meant nothing, specifically, to
Hammond itself, once the contract ran out (or at least I've been told as
much by a Hammond engineer).

Good luck, in any event...!

~73~ Eddy VE3CUI - VE3XZ


***************************************


----- Original Message ----- 
From: "John King" <k5pgw at yahoo.com>
To: <amradio at mailman.qth.net>
Sent: Friday, December 26, 2008 11:22 AM
Subject: [AMRadio] Need help identifying National part


> Have New Old Stock National part number SA1288. Appears to be a
transformer with two spade bolts to bolt to chassis and has the National
diamond emblem which has "NC" in the diamond. It is tar filled and has five
black leads coming out of it. It is shaped like a LARGE IF can but has no
adjusting screws or slots as it is completely enclosed. The dimensions are:
> 4" H X 2 3/8" D X 1 15/16" W. It weighs about one pound.
>
> It is NEW and unused still in the National Box.
>
> Looks like a transformer of some sort such as an audio transformer from
one of the "OLDER" National receivers that had considerable audio output for
a receiver such as maybe a pair of 6V6 tubes or something of that nature.
>
> If you have the facilities to cross reference the part number, I would
appreciate if if you would let me know what it is and which piece of
National gear it was made for.
>
> Your help is appreciated. 73, John, K5PGW
>
>
>
>
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