Audio technica ATM73a poor signal level

by Waigy
(Fife, Scotland)

Hey Man

I've had an ATM73a headworn condenser mike for quite a few years.
I've always had a problem getting a good signal level with it.
Usually whoever is on the mixing desk has to turn the trim and gain up to maximum just to get a normal level.
It usually gets feedback just as soon as it starts to get a level.
When I plug it into my Motu traveler I have to put the trim and gain up full to get a normal level.
I bought an identical second hand ATM73a online instead of paying to get my one serviced.
The one I bought online gets the same signal level.
Is there anything I can do myself to repair the mike, I reckon it might be the diaphragm part of the mike that is maybe dirty or worn.
I've tried what the audio technica service people suggested which was to straighten the pet connector so that it gets a better connection.
That made no difference.

Cheers Man