IF transformers in 1960s Fisher receivers: who made them?

monkboughtlunch

Super Member
The IF transformers in 1960s Fisher tube receivers have similar markings to those used in 1960s McIntosh products.

Were these IF transformers made by a common third party vendor? If so, anyone know who made them?

Below: example Fisher IF transformer.

IMG_4874.jpg


Below: example McIntosh IF transformer

mac.jpg
 
119 is apparently "Automated Manufacturing".

They do look like Miller parts though. Maybe the same company?
 
119 is apparently "Automated Manufacturing".

They do look like Miller parts though. Maybe the same company?

Good catch. I found this 1962 EIA document.

It appears the name associated with 119 was actually: Automatic Manufacturing Division, General Instrument Corp, Newark 4, N.J.

So it appears they were made by General Instrument Corporation's Automatic Manufacturing Division.

I wonder how many high end audio manufacturers used these IF transformers for their tuners and receivers. It appears both Fisher and McIntosh used them extensively.
 
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Are these in the 'K' CAN group that go bad when the sandwich plated mica wafer shunt caps go bad?
 
A picture of a Harman Kardon TA-260 receiver from 1960 below. It also shows they used the same "119" IF transformers!

To what extent was there a common, generic FM tuner reference design used by the middle upper and high end audio manufacturers when utilizing these "119" IF transformers?

And to what extent did those brands like Fisher, McIntosh and Harman Kardon etc develop their own unique "house sound" FM circuits that would differentiate the quality of tuner sound vs competition using similar baseline IF transformers?

hk260.jpg
 
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To what extent have folks here experienced silver mica disease with their Fisher tube tuners and / or receivers?

I found this link to a repair of a Hallicrafters S-107 receiver. There's a picture of a "119" IF transformer which is claimed to have silver mica disease. Here's a picture of the internals of the 119 IF transformer pulled from the Hallicrafters receiver.


View attachment 935402
Yep, that's it.
Less a problem on the AM side than the FM as AM IF can be more easily realigned after repairs than FM, which requires a specialized equipped bench.
 
I know that Sruddy had a dead FM transformer, and Dave G. had one in a 800c I believe. But other than those 2 on here in FISHER Forum nothing that has been posted. So it's a fairly rare occurance. Altho it could develop in later years.
 
I know that Sruddy had a dead FM transformer, and Dave G. had one in a 800c I believe. But other than those 2 on here in FISHER Forum nothing that has been posted. So it's a fairly rare occurance. Altho it could develop in later years.
Have at least one in a 500T and had a few in a Dyna FM-3. I tend to avoid tuners of this vintage as a result as I cannot align FM tuners, which limits me to the later solid state era for tuners generally.
 
Only so many companies were making IF transformers. For whatever reason, the tuner industry standardized on two IF frequencies, 10.7 mc for FM and 455 kc for AM. I suspect that was pushed more by the transformer makers than the tuner designers just to make life easy. Either way if you really started looking into all this and found the cross numbers for various tuners I suspect you'd find that many of them cross reference to the same part numbers.

To be honest, there are only so many ways to pull in a signal. If you look at any superhet tuner, its going to look very much like any other superhet tuner. The only real variables are the bandwidth of the IF transformers and the detector style in use. I suppose the limiter stage also factors in there somewhere.
 
The conversion from the RF to the IF has artifacts in addition to the main difference frequency. Note that both of the above frequencies are approximately half the width of their respective broadcast bands and also at odd frequencies such that artifacts would be between stations. Not sure how much went into this decision but there was a LOT of engineering and compromise when color was added to the TV signals to keep the new signal compatible with old sets and avoid interference between luminance, color, and audio frequencies.
 
A search for "compression trimmer capacitors" will find some.

They are also available from the surplus electronic outlets, although the inventory is variable (see what I did there).
 
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