I have this radio working once again, but the m.a. is 90 m.a. It drops to 5 m.a. when speaker is unplugged. The speaker measurements are 2.31k ohms on the output transformer, and 600 ohms on the other two terminals of the speaker. It has four wires. Two go to the transformer mounted on the speaker and other two go directly to the speaker. As far as the annoying hum goes..have not put radio chassis back in cabinet, so dont know if it will get softer or not. The trans does seem to hum at half the frequency once the tubes start to conduct. I wouldnt think it would be possable to have this transformer hooked up wrong.

:Also the transformer measures 350 volts after the tubes start conducting(filaments warm up). How loud does transformer hum have to be before I need to be concerned?
:
:I have this radio working once again, but the m.a. is 90 m.a. It drops to 5 m.a. when speaker is unplugged. The speaker measurements are 2.31k ohms on the output transformer, and 600 ohms on the other two terminals of the speaker. It has four wires. Two go to the transformer mounted on the speaker and other two go directly to the speaker. As far as the annoying hum goes..have not put radio chassis back in cabinet, so dont know if it will get softer or not. The trans does seem to hum at half the frequency once the tubes start to conduct. I wouldnt think it would be possable to have this transformer hooked up wrong.

Hi Sean

When a radio draws too much current and filters have been replaced, it's usually the output tube circuit. Check grid #1 voltage in ralation to cathode. Grid #1 must be negative. Don't operate the radio very long drawing 90 ma.

Transformer hum isn't a problem. If you can't reduce the noise by tightening screws varnish the core to stop vibrations. It's also possible the winding isn't tight to the core. Sometimes wooden wedges are used between winding & core to reduce noise. You could try that..

Norm

::Also the transformer measures 350 volts after the tubes start conducting(filaments warm up). How loud does transformer hum have to be before I need to be concerned?
::
::I have this radio working once again, but the m.a. is 90 m.a. It drops to 5 m.a. when speaker is unplugged. The speaker measurements are 2.31k ohms on the output transformer, and 600 ohms on the other two terminals of the speaker. It has four wires. Two go to the transformer mounted on the speaker and other two go directly to the speaker. As far as the annoying hum goes..have not put radio chassis back in cabinet, so dont know if it will get softer or not. The trans does seem to hum at half the frequency once the tubes start to conduct. I wouldnt think it would be possable to have this transformer hooked up wrong.

:hello, I have just checked the grid voltage to chassis and it is -14.5 volts. Cathode is 0 volts to chassis. When you unplug the speaker, the amperage drops to 5 m.a.
:
:Hi Sean
:
: When a radio draws too much current and filters have been replaced, it's usually the output tube circuit. Check grid #1 voltage in ralation to cathode. Grid #1 must be negative. Don't operate the radio very long drawing 90 ma.
:
: Transformer hum isn't a problem. If you can't reduce the noise by tightening screws varnish the core to stop vibrations. It's also possible the winding isn't tight to the core. Sometimes wooden wedges are used between winding & core to reduce noise. You could try that..
:
:Norm
:
:
:::Also the transformer measures 350 volts after the tubes start conducting(filaments warm up). How loud does transformer hum have to be before I need to be concerned?
:::
:::I have this radio working once again, but the m.a. is 90 m.a. It drops to 5 m.a. when speaker is unplugged. The speaker measurements are 2.31k ohms on the output transformer, and 600 ohms on the other two terminals of the speaker. It has four wires. Two go to the transformer mounted on the speaker and other two go directly to the speaker. As far as the annoying hum goes..have not put radio chassis back in cabinet, so dont know if it will get softer or not. The trans does seem to hum at half the frequency once the tubes start to conduct. I wouldnt think it would be possable to have this transformer hooked up wrong.

I think the problems was caused by disconnecting the speakers at some time or just a bad tube. It should be noted that a tube circut should NEVER be connected to an impedience higher than rated. The disconnected speaker circuit could have blown the tube. An open in the transformer at some other time or a bad speaker at some time. The transformer that I am refering to is the output transformer. It should be noted that on tube circuits that is is safe to bypass this transformer, but expect a weak output.
::hello, I have just checked the grid voltage to chassis and it is -14.5 volts. Cathode is 0 volts to chassis. When you unplug the speaker, the amperage drops to 5 m.a.
::
::Hi Sean
::
:: When a radio draws too much current and filters have been replaced, it's usually the output tube circuit. Check grid #1 voltage in ralation to cathode. Grid #1 must be negative. Don't operate the radio very long drawing 90 ma.
::
:: Transformer hum isn't a problem. If you can't reduce the noise by tightening screws varnish the core to stop vibrations. It's also possible the winding isn't tight to the core. Sometimes wooden wedges are used between winding & core to reduce noise. You could try that..
::
::Norm
::
::
::::Also the transformer measures 350 volts after the tubes start conducting(filaments warm up). How loud does transformer hum have to be before I need to be concerned?
::::
::::I have this radio working once again, but the m.a. is 90 m.a. It drops to 5 m.a. when speaker is unplugged. The speaker measurements are 2.31k ohms on the output transformer, and 600 ohms on the other two terminals of the speaker. It has four wires. Two go to the transformer mounted on the speaker and other two go directly to the speaker. As far as the annoying hum goes..have not put radio chassis back in cabinet, so dont know if it will get softer or not. The trans does seem to hum at half the frequency once the tubes start to conduct. I wouldnt think it would be possable to have this transformer hooked up wrong.