[Hallicrafters] HT-37 Modulator transformers T102 and T103replacement

[dgervasi]

David, I feel real lucky still having one good one (T102). That will help a great deal in trying to match the level of audio at the grids of the replacement side with those at the still working side when I decide to try something. I was hoping we might get a reply from someone who has already experienced the same failure and found a solution.
I have measured the DC resistance of the good one and find about 40 ohms on the secondary and about a little over 1 K on the primary. The wire on the primary appears to be about 40 AWG and the secondary somewhat larger at the mid 30's maybe 34 or 36AWG. 

When you take all these factors and put them together it appears that the transformers are installed in reverse of the normal plate primary (lower impedance, 10K or so) and the higher impedance (in the case of the Hammond 90K with center tap) going to the grid (s) of the next stage. On the HT-37 it seems the Higher impedance is in the plate circuit and lower on the grid or output side.

Hopefully there is someone out there that knows the answer to that one and is familiar with the design intent of the Hallicrafters engineers in that circuit.




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