[Nuvistor]

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.