1100GTO RA & Dec Auto-Adjust Motor/Gearbox Upgrade (S1100MGW-UP)

May 7, 2025.  We have a limited number of upgrades available for mounts shipped before January 2016 (serial number 11261 or lower). Mounts shipped after this date already have the auto-adjust motor/gearboxes.

We plan to offer these upgrades by appointment throughout 2025 or until we have sold all upgrade components we have in stock. When we are ready to upgrade your mount, we will contact you to make the appointment and issue an RA number. Each upgrade takes at least one day of labor. We intend to complete the upgrade and return the mount to you as quickly as possible.

What are Auto-Adjust Motor/Gearboxes? 

Our motor/gearboxes were designed to be responsive for precision astro-photography, while at the same time making it super easy to use and adjust.

• Spring-loaded worms maintain full contact under all guiding and slewing conditions
• Automatic setting for worm mesh requires no adjustments over long time periods
• Precision balance mechanism allows full backing off the worm from the worm wheel
• Very low backlash gear train eliminates Dec reversal delays and provides high position accuracy during guiding
• Caution: Be sure to completely disengage the auto-adjust motor/gearbox before you move the axis to avoid damage to the worm gear or worm wheel.
  
  

How Do I Sign Up?

• Upgrade valid for mount serial numbers 11261 or lower. Later mounts are already upgraded.
• Mount must be available to ship shortly after we contact you. 
• Complete form: 1100GTO Auto-Adjust Motor/Gearbox Upgrade Request Form

What Does the Upgrade Include?

Items to Return to Astro-Physics:

• RA axis with polar fork
• Dec axis
• Control box
• RA/Dec servo cable
• Encoder cables if mount has absolute encoders

  Auto-Adjust Motor/Gearbox Upgrade includes the following:

• Disassembly and replacement of the following components for the RA and Dec axes:
• Motor/gearboxes boxes and covers
• Worm bearings
• Worm box mounting plate
• Installation of additional new components:
• Adjustable Cam Knob Assembly
• Bearings for cam adjustment 
• Cam cover
• Fasteners
• Clean spur gears
• Reassembly of motor/gearbox
• Adjust and re-grease spur gears and worm gear
• Reinstall and adjust on the mount
• Create and download new PEM curve into control box
• Upgrade control box firmware, if needed. 

These original components will be reused during the upgrade. Additional charges will apply if they need to be replaced: 

• Motors and their harnesses
• Spur gears
• Worm gear

Optional Parts and Services

Optional services are available for an additional charge. This is a great opportunity to tune up your mount after nine+ years of use. 

• Clean and re-grease RA & Dec worm wheels ..... $95
• Install absolute encoders (subject to availability, GTOCP4 is required) ..... $214 (plus cost of absolute encoder kit)
• Upgrade to GTOCP4. The new PEM curve will be downloaded into the CP4. New power cable and other components may be required ..... $1,295
• GTOCP3: upgrade to V2 chip (CHIPKIT2) ..... $92
• Keypad: upgrade from V4 to V5 button pad, update firmware, replace battery or cable .....  based on parts and service requested
• Clean and paint touchup ..... based on time