The hand control of my Advanced GT scope is displaying No response 16 or No response 17. What’s wrong with my scope?

"No response" means that the hand control has lost communication with the electronics board within the base of the telescope.  The number following this message will indicate the address of the component that has lost communication. 16 indicates the azimuth or RA motor board, 17 the altitude (declination) motor board. Unfortunately, this number doesn't tell why the error has occurred.

There are several reasons why this error message would appear.  Insufficient power is the most common. Check your power supply.  If the DC battery is low, the scope will be unable to communicate with the base of the telescope.  If you are using an AC adapter, please make sure that the adapter is rated for an output of 12 volts DC at a minimum of 2500mA (2.5 Amps).  If your adapter puts out less current than 2500 mA, the scope will not be able to communicate properly. Check all power connections including the power port pin for solid connectivity.

The next potential causes: the hand control, the motor control circuit board, the motors, or the cables-wiring-connectors in between.  If these quick fix ideas don't work, it’s best to send the equatorial head and hand control back to Celestron for factory service.

Updated 12/27/13