Its weird because it only cuts out when its tuned to the left side of the dial

Well! If its position specific then its likely mechanical. That comes down to fouling, dry joints, loose tube being pushed by a bad fly lead. Dodgy loose top cap on the a tube most probably converter, eroded fly lead insulation shorting to cans and shields. Loose staved in tops on top trimmer IF cans.

Perhaps we need sharp photos of the pan and top? Probing with a chopstick (not metal) may identify something.

There is more likelihood of an oscillator flashover, at (Closed) lower frequency as that is where the oscillator generates its strongest signal.

Sounds like the tuning vanes are touching.

Touching usually outside very plausible. Its going to have to be checked to eliminate it as cause. Isolate it from tube & circuit. And check it for wire shorts as you do.


You may pick up a short by using an ohmmeter, stator to ground and rotating the vanes into the stator.

It comes back when I tap the tuning knob or the top of the radio

And that gives the highest probability that it is a mechanical fault and is not all that consistent with it only happens at one spot.

If it only happens at one spot then its possibly pulling the bad joint open, or hitting something. If its got a 6A8, or its octal family check the top cap & fly lead for shorting on the can, or check the top cap of the tube and also make sure the fly lead, being towed is pulling the tube to one side causing a make & break fault.

Probe about with a chopstick.

Hi Marrc thanks for the info. Ive been reading this for days but still cant understand what you mean. Can you please put it in easier terms and maybe give me a link to look at?

Thanks mate.

Some things cannot be put any simpler, the later is basically mechanics and observation, whilst keeping your fingers out of the bits that bight.

With the chopstick, which has been mentioned many times, not only on this forum and over a long period. A non conductive, or inductive rod, such as a wood, or preferably plastic chopstick, is used to gently prod components & wires, to see if they are actually soldered properly, losing contact, or in some cases shorting.