[Collins] MM1 mic and filters

[Martin Sole]

A couple of questions for the group.

Today a friend brought me an MM1 microphone, very dirty with a cracked and
crumbling cord but at $4 US the price seemed reasonable :-) Examination
shows that the element appears to be open circuit. The transformer seems
good but the element itself measures o/c. Question, where do I get a
replacement?

Found some Collins mechanical filters. From the information at WA3KEY they
look like type B cases but I cannot locate the type numbers in the list on
that site. Any ideas what they are and where they were used?

526-9041-00  F455 C12 (1.2KHz?)
526-9042-00  F455 C31 (3.1KHz?)
526-9043-00  F455 C60 (6.0KHz?)

The bandwidths above are my guesses based on other filter nomenclature. Any
additional info appreciated.

Many thanks

73
Martin - HS0ZED