The connections for OPTO1 and OPTO2 sensor in the MAC 250 are shown reversed on the label inside the yoke cover. Plugging the sensors in as shown will result in pan and tilt feedback errors on reset.

The correct positions are shown in the user manual on page 26. OPTO1 plugs in next to the 2-pin fan plug and OPTO2 plugs in next to the display plug.