Nate: I've had the same problem with the MH-27 on two radios. After getting the schematic of the MH-27 from Yaesu, determined that a cap had failed (open); C5 (0.1uF). I replaced cap in both mics and haven't had another mic problem since (>5 yrs). Now I need to replace the 2M finals in my 5200. GL - Mike K6QD