DIY Sennheiser m66/67 repair

Hi
I have an M66/67 comination and I think the mic capsule has gone noisy low o/p. With the gun removed the amplifier is quiet and plent of hum if finger is placed on contacts, so assuming pre-amp is ok. The measured voltage on battery mode at the capsule connection points is around 7.5-8.0 volts, is this correct?
Also I would like to remove the mic capsule, is there a way of dismantling the gun assembly. Are there schematics available?
The quote I had from Sennheiser was rather high!
Regards
Andy

Welcome Andy, good to see you over here.

Hopefully someone here will have some information on the M66/67. I haven't worked on these so am afraid I am not much help.

Stewart