Troubleshooting

This is a collection of information that has been useful in the past. Follow the links for more details.

• Shutter won't respond? Reset the controller.
• DSOS problems? See troubleshooting tips.
• Telescope problems?
  • SECONDARY MIRROR CONTROLLER ERROR on the telescope status monitor? This may indicate the focus controller is confused. Try
    UIP> antenna /restart
  • Multiple difficulties at the same time? Scans won't start, the telescope doesn't move, the spectrometer is hung up, scans stop in the middle of integration, etc. Try
    UIP> antenna /restart
    or
    UIP> antenna /restart /nosync
    Do not press the reset button or power cycle the antenna computer unless you are certain a hard reset (powercycle) is needed. Further information here or here.
  • Tlength large? This is the angular distance between the dome and the telescope. It is small during normal operation so any significant value indicates a fault. A misalignment of 0.1° corresponds to tlength about 0.075. If tlength is positive, the telescope azimuth is smaller than the dome azimuth. The control system stops the telescope if tlength exceeds about 0.250.
• Heterodyne receiver problems? See troubleshooting tips.
• For SHARC II, don't specify a fixed focus (or X, Y, or theta) position. Instead use a focus offset with constant updates:
  UIP> focus /constant
  or
  UIP> instrument sharc2
UIP> focus /offset NNN