I have GE DMR+ with error E51 158/019 lateral collimator. I have service manual where write "check for play between collimator lateral motor axis and pulley (screw not tightened). Possible problem with 800PL1 (Gantry power board)." I tightened the screw on puley but the problem is same. Does any have idea what problem may be on 800PL1.