Main problems

There were two faults that caused more than 2 hours downtime during period 44, but the cause of the problem was related so I discuss it together below.

• 2012-02-22&24: Altitude motor: 6hr 0m

  The telescope stopped tracking and it moved to pointing to the horizon. It was found that one of the altitude motors did not work any more. The brushes for the motor were replaced and the telescope worked again, but pointing the telescope to several targets nothing was seen. It was found the next day that one of the mirror load cells was out of position effectively misaligning the main mirror. We believe this was due to vibration caused by the problems with the brushes of the motor. In the mean time we have updated the TCS software to detect the start of any strong vibrations and power off the telescope to protect it.

  Two nights later intermittent problems appeared with the telescope motion in altitude. A thorough investigation the next day showed that one of the brushes that was installed in the altitude motor had been pushed in too far. All the brushes were removed and new ones were installed. The main problem is the very difficult access to the area where the brushes are installed. A new tool was made to avoid pushing in the brushes too far.