AF11x trannies
 

Wonder why they had a screen ? they are definately a fault waiting to happen re internal whisker growth , I also suspect they made a small fortune for radio repair shops back in the days when radios were actually sent for repair rather than thrown in the bin

Re: AF11x trannies
 

We didn’t make that much money repairing them, had to keep repair costs as low as possible or even then they would have been scrapped, but yes I did repair quite a few.

Has for the screening, some were designed for use at VHF, probably as cheap to keep the whole line the same encapsulation. It’s also possible that they were graded when they came off production line for use at different frequencies so the encapsulation would need to be the same.

Re: AF11x trannies
 

Hindsight's a wonderful thing. Had they known about whiskering (or for that matter synthetic rubber formulation ageing) in advance...

Re: AF11x trannies
 

Received wisdom for most of us, is that these new-fangled solid-state devices would last indefinitely, and that has, by and large, proved to be so.

Even if you don't earth the "screen" wire, and leave the metal can floating, the whiskers can still take their toll by growing out from the can to two parts of the crystal, or their internal connections.