I have an old TRF battery set, with low volume. Voltages B and A seem good, tubes test OK. But I'm wondering about the audio interstage coils? How do I check those on what pin of the tubes, and what resistance should I see?

Hi Jack

Use your ohm meter to check for continuity. Audio interstage transformers will have resistance in the range of 500 to 10,000 ohms. There are two windings, primary and secondary. The primary will usually be lower resistance.

Don't worry about exact readings. The windings should be ok or open. It's very common for Audio Interstage Transformers to have an open winding.

Norm

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:I have an old TRF battery set, with low volume. Voltages B and A seem good, tubes test OK. But I'm wondering about the audio interstage coils? How do I check those on what pin of the tubes, and what resistance should I see?

Have the trimmers on the tuning condenser gang (if it is a gang) been aligned so that the set synchronizes? Any leaky fixed condensers? Make sure your antenna is long and high. If your TRF has 2 tubes or less in the RF section, it won't be that selective or strong, so a long antenna is needed. Lot more to a radio than tubes and voltages.

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:I have an old TRF battery set, with low volume. Voltages B and A seem good, tubes test OK. But I'm wondering about the audio interstage coils? How do I check those on what pin of the tubes, and what resistance should I see?