01-04-2009, 04:53 PM
I purchased a Stromberg Carlson model 561 which is a six tube superheterodyne receiver designed for operation on either DC or AC currrent. It did power up and receive some stations but with a loud hum at all volume levels and after a few minutes of operation at higher volume levels output would become intermittant and garbled. I ordered schematic and engineering info as well as electrolytics and other capacitors. After recapping the hum was gone and the radio performed nicely until after a few minutes the output became garbled at any volume above around twenty five percent. This is my first attempt at working on a tube radio and don't know where to go from here. I understand that there may not be much you can tell me without engineering info in front of you, but I was hoping that this may be a common problem and you could suggest where to begin looking. Also there one other thing about this radio that I am not sure is normal. When first powered up the dail light turns very dim and then brightens as the radio warms up. Thanks Gary