The AM Forum

Most T-17 carbon mics do not work. A replacement is the Shure 101C, 103C and 104C series carbon hand mics. Some of these Shure mics have bad elements. A replacement are carbon telephone microphones.  A benefit of a telephone carbon element is the frequency response is usually 6kHz where as the Shure are limited to 4kHz. Good carbon elements measure in-between 100 to 150 ohms.

Back in the 1950's it seemed common to replace the head on a T-17 with the mike cartridge from a Western Electric 200 or 300 series home telephone.  There was a mic cartridge for a Western Electric 200 series telephone that had sort of a bullet shaped Bakelite part on the front.  I have a couple T-17's where someone installed those and wrapped the outside up with electrical tape. Ugly but works.  There was an article in CQ or similar many years ago about adapting telephone cartridges to T-17's but of course the topic was mainly mechanical modifications.

Old Motorola police radio mikes will also generally work. Originally carbon types, when Motorola switched to plastic housing mikes they also started using dynamic cartridges with a transistor amplifier inside which would also substitute for an older carbon type. They just look out of place on military gear.