1139   Error: Turbo pump not at target speed in Standby mode.

The number of revolutions of the turbomolecular pump went below the limit (In Standby mode).

Check the number of revolutions and the current of the turbomolecular pump, vacuum pressure (AN), vacuum pressure (IF/BK), and power voltage. The following are the probable causes.

• An increase in the vacuum pressure.
• The connector of the turbomolecular pump came off.
• Faulty Power Supply (24 volt).
• Faulty turbomolecular pump or turbomolecular pump controller.
• There is a fault in the Connection PCA.