Dome shutter won't open
Ice can seal the dome shutter so it won't open. If this happens, switch off the toggle switch on the side of the dome relay box (which is on the north wall, left of the toolbox). This cuts power to the motor and will prevent overload and damage.At this point the TCS computer is still commanding the dome to open. You should clear this situation by waiting for the message on the TCS screen about the dome opening to go away, then commanding the dome closed. You can also restart the TCS for a similar effect.
Except for noting the situation in the ptlog, there's nothing else to be done; you cannot observe.
Dome won't turn
We've never seen dome rotation failures caused by ice or snow. If it happens, however, we suggest unplugging the dome rotation motor (the power cable going from the dome rotation relay box on the east wall to the receptacle behind the desk near the floor). This keeps power off the dome rotation motor, preventing overload damage in case the motor is activated unexpectedly (this has happened due to handpaddle switch failures). Note the "HALT MOTORS" button does not disable power to the dome rotation motor.HOME