Adjusting the backlash on a Skywatcher EQ35

We'd like to show you how to adjust the backlash, or play, of the DEC worm gear on a Sykawatcher EQ35.

Tools required:

2.0 mm Allen key
2.5 mm Allen key
4.0 mm Allen key
Phillips screwdriver

Step 1: Remove the motor housing

To access the worm gear adjustment screws, the motor must first be removed. Therefore, the two Phillips screws are loosened to access the motor.

 

Step 2: Removing the DEC Motor

Using the 4.0 mm Allen key, loosen the motor retaining screw, then remove the motor.

 

Step 3: Adjusting the worm gear play

First, check the gear on the worm gear axle for play. A 2.0 mm Allen key is required for this.
 

The worm gear play is finely adjusted using a 2.5 mm Allen key and two 4.0 mm Allen screws. The worm gear movement should be smooth but not stiff.

I've found that the procedure is to first slightly tighten the two outer screws, then the middle one. If they're too tight, they can be slightly loosened again in this order. This is repeated until the screw movement feels as described above.

Step 4: Assembly

After that, the whole thing can be reassembled. The backlash problem is completely resolved.