[Sideband]

You could try removing valves one at a time starting with the mixer and work back. One of the valves may have a heater/cathode short which will cause hum. Try removing the mixer, switch on and check for hum. If it's still there, refit the mixer and remove the I.F amp. Check the set again. Repeat the procedure for the AF amp/detector. If the set still hums at this point, it's either the output valve or rectifier (unlikely the reccy as this would cause other problems with possibly a repeat of the damaged transformer). With just the output valve and rectifier in place, there should be very little hum from the speaker.


Rich.