[TenTec] Jupiter w A/T ettings for Digital (PSK31) Communications

[jimimaxi2 at comcast.net]

I have problems with power on my screen dropping to zero as I transmit in digital. 
I tune to 1.0.0. My power is close to 30% which translates to about 20-23 watts on the screen. Mic gain is zero. TX Filter BW is at 1050. Audio source is at line. Speech Proc is at 0. Mic Boost is at 0.
I use a Donner Digital Interface to a USB port with a separate serial cable connecting the PC to my Jupiter for rig control via HRD. I use Digital Master 780 for the digital side.
At times I get a clean output (TX and ALC light up), but at other times I drop to zero on the sceenand only the TX light appears. When this occurs a receiver near my desk shows nothing. I can return to a good watt output by increeasing Mic Boost to 12db.
Does anyone know if any of my settings are wrong? Or any other help I may need.
Jim
KC2ROF