Icom microphone listing
Your Icom IC-730 was factory shipped with the Icom HM-7 hand microphone. See page 3 of your Icom IC-730 manual.
The schematic diagrams for the HM-7 and SM-5 microphones are on Page 4 of the IC-730 Owner's Manual.
The Icom HM-10 was designed and sold (option) to work with these Icom radios: 25A, 251A, 255A, 260, 290A/H, 451, 490, 730
It has an 8-PIN "Foster" circular mic connector and uses a DYNAMIC microphone element.
Photo is attached
As you can see from the attached photo, this microphone is a bit complex (PC board inside).
The imporant thing is to FOCUS on the basic FIRST. Microphone Audio and PTT function.
This will use 3 or 4 wires (IF the grounds are shared between the MIc and PTT functions)
THEN move on to UP/DOWN and Scanning functions.
The Icom IC-730 Owner's Manual will have the mic connector PIN usage/function -- that you can trace (VOM/DVM using continuity function) --
to wires inside the microhone case (and to PC board). One may be +8 VDC to power and transsistors or other active electornic device inside.
ICOM is the only Eastern Asia manufacturer that provides ALL of their product manuals (radio and accessory) for download
by radio amateurs via the Internet -- FREE (no memberships, fees or other such nonsense).
IF the manual you need is NOT shown, a simple request on their contact sheet will produce a scanned PDF from their paper document library
within a week (4 to 5 business days).
I have used this service since it was first offered and I have been very pleased with Icom's responses and support.
We keep moving forward, opening new doors, and doing new things, because we're curious and curiosity keeps leading us down new paths. -- Walt Disney