Partner Plus Line problems

[Mongo5150]

I have a good one I need help with. Partner plus with Partner mail (stand alone) When a call comes in the phone rings 1 time then the lights go off and do not rinng anymore. BUT, if you call in, you hear the 1 ring then silence. If the person picks up the handset and hits the line that rang 1 time, the 2 people are connected. Its like the system is grabbing the call after one ring, but there is no lights on that line to indicate a call. Put but-set on lines at demarc, everything fine there.
I took the lines out of the voicemail hunt group and shut down voice mail. Didnt fix problem, so I assumed processor. NOPE, swapped out processor. Then figured it was the 206 cards. Swapped them out but did not fix problem. Only thing left is the carrieer....right? Am I missing something? Cant be ASA (Partner PLus).....Help

 

[TouchToneTommy]

There may be a station port that has a high resistance short on the voice pair. Not low enough to take the station off hook, but enough that when the 90VAC ring comes in the port shorts and "answers" the call. Remove ringing from all sets, then call in and see if it happens. Then add ringing back one station at a time, until you find the station that auto answers itself. Check the station, wiring, see if it happens with nothing plugged into that station port.