On Dec 20, 8:05*am, "xpyttl" wrote:
But if the objective is to actually -use- the amp, then a micro and an LCD,
along with a little design work, can lead to a meter that is more accurate,
more robust, and cheaper than the original.

I have to disagree here. For time-varying parameters of great interest
- certainly plate current is the most interesting, but only a little
behind is plate voltage - analog meters, and them bouncing up and down
in response to modulation, are essential to correct operation and
maintenance.

Bargraph-type LED or LCD meters are popular on recent equipment, and
while they have the visual trend to the eye and also lack moving
parts, they still aren't up to the same snuff that good old fashioned
analog meters have.

The thought of watching modulation peaks using a digital panel meter
is laughable. Maybe if you're sending an unmodulated carrier it would
be of value!

Tim.