Due to some lost messages, i can not recall ,who was asking about the supplier of solid state voltage regulators and new gen.alternators , here are the links and you have to contact the supplier , provide the serial number of the aircraft and then they will recommend you , which types,
Alternators can also be bought from Hartzel( which i did) and they have STC for C337. attached also FORM 337 for minor change to install this stuff.
https://planepower.aero/product/airc...ge-regulators/
https://hartzell.aero/pma/?selection=alternators
and also picture of antennas location ,as some body was asking it to
Regards
Dennis