i have a kenwood tm-241a radio with the mc-44 mike. when you press the ptt button the radio stays keyed. if you jumper the ptt to ground the radio keyes and unkeys ok. diodes d2 and d3 appear open. the three chip transistors on the back of the board check ok. anyone have a shecmatic for this mike to tell me what kind of diodes these are? thanks, ed N4EK