stewart - warner 300

[stusnyder]

I picked this up at kutztown for 8 bucks, clean and all there except for the tubes. Very good condition set. I hooked up a speaker, put in a set of known good 201's, hooked up the battery eliminator, and was greeted with static.
Could not manage to tune in a station. I assume the center dial is the "coarse" tuning and the others are "fine " tuning. Anybody have any pointers how to tune these?

[Electronic M]

I believe that one should rotate all knobs in unison so they stay at about the same position then when a signal is heard each one is tweaked seperatly for maximum volume. But what do I know, I've never owned a TRF set that did not have the three tuning caps connected together mechanically. So this procedure is merely a guess.

[truetone36]

have you tried hooking up an antenna? IIRC, these sets need an external antenna to pick up much.

[stusnyder]

Originally Posted by truetone36

have you tried hooking up an antenna? IIRC, these sets need an external antenna to pick up much.

Yep, got a 100 foot long longwire outside...

[Reece]

Electronic M is right, you need to keep the three tuning caps in about the same position. Put a strong local station on another radio and look at how the tuning cap is meshed. Then put the three tuning caps on the Stewart Warner in the same position and try. Each will have to be tweaked to max the signal.

This hassle is why the mfrs. worked so hard to get one-knob tuning!

[stusnyder]

Originally Posted by Reece

Electronic M is right, you need to keep the three tuning caps in about the same position. Put a strong local station on another radio and look at how the tuning cap is meshed. Then put the three tuning caps on the Stewart Warner in the same position and try. Each will have to be tweaked to max the signal.

This hassle is why the mfrs. worked so hard to get one-knob tuning!

I'll try it tonight, thanks for the tips!

[stusnyder]

I checked it out more last night and it seems like one of the transformers is not getting power to it.

[wa2ise]

Originally Posted by stusnyder

it seems like one of the transformers is not getting power to it.

Sometimes the rosin in the solder used back then was a bit corrosive on the fine copper wire. Sometimes careful resoldering to bridge the break might fix it.

[stusnyder]

Originally Posted by wa2ise

Sometimes the rosin in the solder used back then was a bit corrosive on the fine copper wire. Sometimes careful resoldering to bridge the break might fix it.

Worked on it tonight, I do have power in and out both transformers. Checked out everything else and did not find anything obvious. 2 capacitors in entire radio. No value listed on them or in schematic. Anyone know what value are these?

[Reece]

They used transformer coupling in these sets as it gives more gain. R/C coupling will generally give better fidelity but less gain; however, you may be satisfied with the volume you get, and on a typical twenties speaker, the better quality may not be noticed anyway!

[stusnyder]

Originally Posted by Reece

They used transformer coupling in these sets as it gives more gain. R/C coupling will generally give better fidelity but less gain; however, you may be satisfied with the volume you get, and on a typical twenties speaker, the better quality may not be noticed anyway!

The volume is really good, in my opinion. I was surprised how loud it goes.

[leadlike]

Are you listening through headphones or a speaker? I've found headphones (especially Baldwin type Cs) much better for critical listening on these 3 dialers.

[stusnyder]

Originally Posted by leadlike

Are you listening through headphones or a speaker? I've found headphones (especially Baldwin type Cs) much better for critical listening on these 3 dialers.

Thru a speaker, with a good range of volume.

[stusnyder]

Heres some pics of the transformer, the first is the temp circut I hooked up to test the radio, next is the coil of the tansformer. One winding is broken internally. The last pic is all the pieces of the transformer.
What I'm doing now is cutting the center tab out of each plate, so when it's assembled, it will be hollow to mount the resistors and capacitor inside.

[stusnyder]

here's he gutted out transormer with the 2 resistors and capacitor mounted inside. I think it turned out real nice.