Only 49 ac volts to auger motor.

Auger motor stopped during regular use, and will not come on at all any longer. Motor works fine with 115 ac volts applied, but multi-meter is showing only 49 ac volts at stab connectors to motor. Suspecting circuit board. Motor fuse intact. Have checked continuity, tested, or bypassed every single switch, one at a time. Boards are too expensive to be just parts swapping.

Hello
Yes check the Vacuum Switch and hose, the Low Limit Switch and High Limit switch or Heat Sensor. It there is a Hopper Lid switch or Fire Door switch check those.
You can also check the voltage coming out of the board where it goes into the first switch and a white neutral wire. If they all check good then it can be a bad Triac on the control board so the board should be replaced.