I have a Mongomery-Ward Airline 04WG-731B that's really giving me trouble. When it's first turned on, both the 14V dial lamp and the 6L5G (2nd Det.) filaments burn brightly, but then quickly dim down. I checked the voltages on all 7 tubes (with a digital multimeter) and found the voltages were all ok, except for the 6L5G (1.2V) and the 35Z5 (30V).
When the set is turned on and with me (ungrounded!) touching the chassis, I can pick up shortwave signals clearly, but AM signals are distorted with a 60Hz hum. All paper caps have been replaced, and all wires to the built-in antenna have been disconnected. I've checked all the ground connections under the chassis and they look good. I've probably overlooked something. I would deeply appreciate any suggestions from anyone that would help me get this set going.

Thanks in Advance,
Larry Rickard

Hi Larry

It's not unusual for that action in a series wired filament radio. The dial light will flash brightly on turn on, then dim and brighten again when the radio plays.

Is that 1.2 volts on the filament of the 6L5G? If so, it's too low and the tube may be bad. Try another 6L5G or 12J5.

Do you hear hum with the volume control down? If so the radio may need filter caps. If there isn't hum with the volume down check the loop antenna connections. You do need the built in antenna connected as it's also the antenna coil.

Norm

: I have a Mongomery-Ward Airline 04WG-731B that's really giving me trouble. When it's first turned on, both the 14V dial lamp and the 6L5G (2nd Det.) filaments burn brightly, but then quickly dim down. I checked the voltages on all 7 tubes (with a digital multimeter) and found the voltages were all ok, except for the 6L5G (1.2V) and the 35Z5 (30V).
: When the set is turned on and with me (ungrounded!) touching the chassis, I can pick up shortwave signals clearly, but AM signals are distorted with a 60Hz hum. All paper caps have been replaced, and all wires to the built-in antenna have been disconnected. I've checked all the ground connections under the chassis and they look good. I've probably overlooked something. I would deeply appreciate any suggestions from anyone that would help me get this set going.

: Thanks in Advance,
: Larry Rickard

Thanks for the quick reply! I forgot to say that the 1.2V is on the filament. I'm new to this hobby, so it didn't occur to me that the tube may be bad. It tests good on my tester (the filament shines like a light bulb), but there's no substitute for testing in a circuit...
I also forgot to mention that all of the electrolytics have been replaced.

Thanks again,
Larry

Larry

Earlier you mentioned all the wires to the built in antenna are disconnected. This could be your problem. Most of these radios use the built in antenna as tuned coil for brodacast band. Without the coil you will have weak signals and hum.

I don't know what is wrong with your 6L5G tube. It may have part of the filament shorted. The tube should have 6 volts across the filament. Since the radio does pick up short wave this doesn't seem to be a problem. Sometime you may want to replace the 6L5G. A 12J5 may be easier to find and will work in your series wired radio.

Norm

: Thanks for the quick reply! I forgot to say that the 1.2V is on the filament. I'm new to this hobby, so it didn't occur to me that the tube may be bad. It tests good on my tester (the filament shines like a light bulb), but there's no substitute for testing in a circuit...
: I also forgot to mention that all of the electrolytics have been replaced.

: Thanks again,
: Larry