[Hallicrafters] Need Help With SX-101 USB Problem

[richard]

Hello.
Have a SX-101 that  when I go from USB to LSB & then want to go back to USB it is Dead but if I pull the 12AT7 tube out & put it back in then the receive in USB comes back on or if I turn the on & off many times then the USB receive comes back on yet the LSB never goes out.. Any body have this problem & if you fixed it can you tell me how? I have even put a small fan inside & that does nothing .
Thanks Much
 Richard

Richard Morris