Thanks, Mark. It could be interesting to try adding that LCD display to the
little Bell & Howell. That may nor be possible, though. It has a big do all
chip in it that may prevent accessing the desired point in the circuit.

But I can think of a lot of old tube types, military and civilian, that such a
dislay would be great to have and possible to connect to.

I have a good Optoelectronics frequency counter, which I'll probably need to
use in the investigation.

Bill, K5BY