[Boatanchors] HT-4B Modulation

[Barrie Smith]

 Hello:
I'm having some modulation problems with my HT-4B.

On the air reports state that I've got lots of RF, but very weak and distorted audio.

I get no audio at all when using the BC-614, so I'm using a 600 ohm amplifier.

I've not used the transmitter for several years, so an electrolytiic could have gone bad during that time. Although, no one has indicated that I have hum on my signal.

I remember that the modulation meter used to move up and down rather smoothly when I spoke. Now, it is either at idle current, or jumps up very high and quickly.

In an effort to isolate the problem, I'm thinking of coupling the 600 ohm speech amp to the grids of the 100THs. If I get good modulation under those circumstances I'd know the problem is in the 2A3 stage.

My problem is that I don't know what transformer to use, or where to get it.

Any help finding the correct transformer, or any other ideas resulting in a fix greatly appreciated.

73, Barrie, W7ALW




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