condenser mics

Are powered (2 wire, 3 volt average) condenser mic's noted for
losing their gain, producing crappie audio or both over time?

As I don't do that much repair work, I have some equipment
the owner states is producing low audio on TX. I can not see
anything wrong via the service monitor. So, i've deduced that
maybe the mic element is just producing crappie audio, which is a
2 wire powered condenser type in an standard HT dual band.. 150mhz&440Mhz.
What do you guys think?

P.S.
I don't have a real service manual for this unit, but I have
measured the injected deviation voltage at the varicaps of the
oscillators for the VHF and UHF.

They average around 200 mv PP via a normal audio conversation.

The modulation index seems to be correct on the service monitor.


http://webpages.charter.net/jamie_5";

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