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  #11  
Old 09-07-2015, 03:42 PM
walterbeers walterbeers is offline
Old TVs are better!
 
Join Date: Jun 2011
Location: Omaha NE
Posts: 463
Well, problem solved. It was the 2nd IF can which I was able to get from Moyers. Replaced it, and aligned the coil to 455 Khz, and radio plays fine. Only problem that is still there is a low level 60hz hum even with the volume turned all the way down. Filter caps were replaced with new ones, and hum still remained. Even if I pull the 50C5 while the radio is powered up (with the volume control completely down), there is still 60hz hum from the speakers until the tube filaments cool off. The odd thing about this radio, is that part of the audio output transformer has a winding that I assume is also used as a filter choke for the power supply in series, between the 50uf and the 30uf with the 1.2K 1 watt resistor and the 2 capacitors. I don't ever recall a 5 tube radio using a tapped audio output transformer. (See schematic in post #4). I solved the problem though with replacing the 50uf with a 220uf 160 volt capacitor, which brought the hum down to a acceptable level. Apparently the higher capacitance does a better job of filtering out the 60hz ripple. Strange, but radio now plays fine.
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