Problem with Philharmonic.

[jonathan dollimore]

I know it’s notoriously difficult to diagnose faults remotely, but I’m a bit stumped and so decided to ask. My philharmonic has developed this problem: essentially, it’s behaving as if it hasn’t got a good aerial when in fact it has-  ie poor sensitivity and poor signal to noise ratio. However if I beam a signal to it from an SS tran AMT3000 transmitter, it works very well. Any thoughts?

[Norman S Braithwaite]

The "audio diode" is actually a pair of coils tuned to the IF frequency and providing the audio signal and AGC voltage from the diodes in the 6B8G tube.  The diode(s) are actually in the tube!  The component would have been better labeled audio diode coil.

Norman