Here's a source for the service manual: http://www.mimedical.com/valleylab_force2.htm
But, that might not have complete board level schematics anyway. And, they probably want to sell them...for more that a student can afford.
You might go directly to Valleylab and explain your need. Or, if there are any large community or University hospitals in the area, they might be willing to help out a student.