1966 GE AA5 noise

[maxhifi]

Hi,

I've got a cheap plastic GE 5 tube AA5 radio which is giving me some issues. It is one of the ones built on a single circuit board, and slotted into the cabinet. Very light and cheap, not even a single screw used in the radio!

The issue is that when tuned between stations, there is a loud rushing/rumbling sound. The sound goes away totally when you ground pin 7 of the 12BE6 through a capacitor, and mostly when you ground pin 1 of the 12BE6. Other radios do not pick up the same sound, so I cannot blame the ambient environment.

I'm trying to figure out where it is originating from to no avail - the resistors I have checked test fine, and the AVC circuit appears to be working properly.

I am thinking it is probably not the IF transformers, since the noise goes away when the 12BE6 grids are grounded, and I also have tried to substitute both the 12BE6 and 12BA6 without any luck. The 12BE6 does get hotter than I'd expect it to.

Any ideas would be appreciated!

See video here for the issue: https://www.youtube.com/watch?v=51Jm8qgZKdA

-Max