I'm working on a 6 tube battery set by Stewart Warner, model number is unknown but I'm guesing its in the one of those listed (on one page) for a whole range of models in the 1927 to 1928 range. I can pick up 3 local AM stations but volume is weak, I'm running on about 75 volts B voltage, detector is about 30 volts. A filament voltage is about 4.4 v volts using 6 201As. Coils check OK, audio transformers are at about 7k resistance. There's no trimmers on the set, would it be just a matter of low B voltages?

I would bump up the B+ to 90V, and see what happens.

Next, check the antenna ckt.
Doug

Greetings, how would one bump up the B+ voltage? please forgive my ignorance.
Vinny A.

For these battery-powered TRFs, most people use a battery eliminator, such as the ARBE III or the kit from AES. They provide various B+ voltages, e.g., 22, 45, 67, 90, and 135.
Doug

:Greetings, how would one bump up the B+ voltage? please forgive my ignorance.
:Vinny A.

:I'm working on a 6 tube battery set by Stewart Warner, model number is unknown but I'm guesing its in the one of those listed (on one page) for a whole range of models in the 1927 to 1928 range. I can pick up 3 local AM stations but volume is weak, I'm running on about 75 volts B voltage, detector is about 30 volts. A filament voltage is about 4.4 v volts using 6 201As. Coils check OK, audio transformers are at about 7k resistance. There's no trimmers on the set, would it be just a matter of low B voltages?

One of the coils may have shorted turn(s), or there could be a bad socket or tube. I have seen sets where there is enough inherrent feed back / coupling that they 'work' (strong local stations) even with one tube removed. Also, there are probably neutralizing capacitors somewhere; may not look like an adjustable capacitor - a wire which moves in and out of what looks like a piece of tubing. Ed M.

Ed's suggestion is good: Clean all the tube sockets and make sure the pins and making good contact.
Doug
:
:One of the coils may have shorted turn(s), or there could be a bad socket or tube. I have seen sets where there is enough inherrent feed back / coupling that they 'work' (strong local stations) even with one tube removed. Also, there are probably neutralizing capacitors somewhere; may not look like an adjustable capacitor - a wire which moves in and out of what looks like a piece of tubing. Ed M.