Fan for the high vacuum pump is not operating

This refers to a condition where the MSD is on (at least the foreline pump is operating) but the fan for the high vacuum pump is not working. You can determine this by listening or by putting your hand next to the ventilation slots on the front of the instrument. You should be able to feel the flow of air being pulled into the MSD.

If this occurs, first switch off the MSD. Wait about one minute and switch the MSD back on. If the fan is still not operating, check for the following.

Note The MSD contains a second fan in the electronics module. It is more difficult to tell if this fan is working correctly. The electronics module fan is not user serviceable.

Disconnected fan cable

  1. Remove the upper and lower MSD covers.

    WARNING! Do not remove any other covers. Removing other covers may expose hazardous voltages.

  1. Make sure the fan cable is securely connected to the connector on the MSD frame.

Disconnected high vacuum signal cable

Make sure the high vacuum signal (HIVAC SIGNAL) cable is securely connected to the back panel of the MSD. If the cable is not connected, the high vacuum pump will not turn on.

Malfunctioning fan

  1. Vent the MSD.

  2. Remove the upper and lower MSD covers.

    WARNING! Do not remove any other covers. Removing other covers may expose hazardous voltages.

  1. Disconnect the fan cable.

  2. Make sure the fan blades rotate freely, smoothly, and quietly. Bad bearings will make noise or feel rough as the fan turns.

  3. If the fan is bad, replace it.

See the MSD maintenance documentation for instructions for replacing the fan for the high vacuum pump.