Partyline: How to configuring AB-120 for headsets with electret mics

Question :  I can't get the sennnheiser HME 26-ii(600) to work with the AB 120 Broadcast box. When I press talk, the mic works for maybe 2 seconds I'm using the sennnheiser HME 26-ii(600) with a Clear Com AB-120 broadcast box and am having issues getting it to function correctly. when i press the talk button the microphone immediately works but only for a couple seconds and with deteriorating levels over those 2 seconds. like the plates charge and then discharge but that's it. Seems as though its not getting a bias voltage. Does anything have to be changed to allow preening of electret mic or to activate phantom power? Any thoughts on this would be a great help. Thank You.
Answer: To make the AB-120 support your headset type. It requires you to jumper (link together) pins 5 and 6 on J7  - the brown 8 pin connector at the end of the longer cable connected to the headset jack. If you open the case and face the circuit board with the connector end of the case facing you the pins are numbered from right to left. You should see a black wire on pin 1, a yellow on pin 3, and a green one on pin 4. Use a wire to jumper pins 5 and 6 and you should be in business. 


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