CPC 9.25 declination drive knocking

[Duke2k]

I have a Celestron CPC 9.25 and a knocking sound began to come from the declination drive while tracking. The noise stops when slewing the drive in any speed but returns when tracking.

The noise was intermittent and sometimes quite loud and so I looked online to see if this is a common problem and to find a cure.

Several people reported the same fault but I couldn't find any information or images of the inner workings or how to fix it.

I carried out the following three weeks ago and the knocking noise has stopped since then.

To do this you will require the following items.

1 set of metric allen (hex) keys,

2 small O rings (see image)

Small phillips screwdriver

Lithium grease (optional)

Begin by locating the hex screw on the declination clutch knob (see image)

Undo this screw and turn the knob anticlockwise until it comes off the spindle.

Locate the six hex bolts on the inside of the fork arm and remove them. The bottom and middle screws are the same but the top pair are longer but both different lengths. You may have to move the ota to access these.

Locate the two lower hex bolts inside the bottom hand recess and loosen them but don't remove.

The outer plastic cover should now come off revealing the motor assembly (see image).

Look for the two small black phillips screws that secure the gearbox to a shiny silver pressed steel bracket (see image).

Note that there is a gap between the bracket and gearbox and this is where the O rings will be placed.

Remove one screw and slide an O ring in place, replace the screw and tighten slightly to put pressure on the O ring but not to significantly distort it.

Repeat with the next screw.

While the side plate is off, now would be a good time to replace the grease on the main brass worm and large cog with something suitable like lithium grease.

That's it!

Simply replace the cover and clutch knob and things should be  quieter.

[A40farinagolf]

Hi,

Touch wood mine is noise free so far but thanks for the detailed thread - I've save it just incase.

Hopefully you won't have any further problems.

I'll be viewing the moon later tonight, hopefully the rain will have cleared the skies a bit.

Regards,

M

[Stu_2011]

Hi

Good update and sounds like an easy fix.

Thanks

Stuart

Sent from my iPad using Tapatalk