Michael Tope wrote:
> I am checking out a Ten-Tec Centurion 422 (2 x 3-500z) amplifier for
> a friend. This morning I fired it up on 20 meters (into a dummy load)
> for this first time. Everything looked good (output power, tuning,
> etc) except for the plate current meter. For some reason the plate
> current meter on this unit overshoots horribly (close to full-scale)
> and then oscillates back and forth a few times (~+/- 200mA) before
> settling to the key-down reading. Is this normal for this meter? The
> grid current/multimeter doesn't do this, nor does just about any
> other meter I ever seen.
No...my Centurion meter does not act this way. A likely possibility
could be that it is indicating what it is actually seeing--some type of
parasitic or instability. Try subbing an external meter if you can (I
mean VOM or whatever-I realize you will not have a spare Centurion
meter) and see if it acts the same way. I suspect it will.
The only control that appears to be in the circuit is R1 (10 K pot) on
the 81540 Display board that is used to set the correct value of plate
current.
!!!! BE CAREFUL AROUND HIGH VOLTAGE !!!!
Good luck es 73,
Carter K8VT
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