[Milsurplus] T-368 Carbon Microphone Question(s)

K3PID Ron.K3PID at sbcglobal.net
Sat Jan 28 13:13:35 EST 2017


My Carbon Microphone (M-29B/U) is always in line. That is even when the T3 is not keyed either by the “Continuous” keying switch or by the push button on the mic.  

J11 on the T3 seems to be wired per print but I can not find wiring for the inside of the mic.  The switch in the mic is a DPST with one contact used to key the xmtr ( that works fine) and the other contact is fed from the carbon mic element and switches it to pin E on J11 which shows No Connection on the print and indeed has nothing connected in the xmtr. I have prints for basic thru series E Modulator decks and none show a connection to J11/E. Is there a mod that I am missing?

More info --- I found MIL-DTL-11193E ( the detailed specifications for the M-29B/U carbon microphone set. It has full details of the mic wiring and my mic is wired per print. The problem is that in order for the mic feed to be switched with the DPST push to talk button, something has to be connected to PIN E of J11 in the T3! Either the line running to the gain pot R16 or the bia supply both of which are currently connected to PIN C of J11 and therefor not switched....  

CAN YOU TELL ME if the mic element is normally hot all the time as indicated by the print or does it get switched by the PTT button on YOUR T3?

Still confused ( normal state...)
Ron K3PID
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