4 replies to this topic

[Grumpy Old Man]

All.

Still struggling with the CGX. although alignment is easier with the new CPWI software and by having a web cam fitted on the spotter scope (best thing I've done so far by a country mile!!!).

On rotation, I would hear a very loud rumbling almost grinding sound from the mount. I recall people used to talk about a noise and even record it and post it. Most of the replies were "It's normal for that mount".

Well today I took the covers off and noticed some things with the belts.

Firstly the gear alignment is very poor from the factory and the belt rides partially off one of the gears. I repositioned them best I could but by design, they just don't line up.

I also noticed that if I quickly pressed the buttons on the hand controller to move the motor back and forth, there was a tiny amount of slop in the drive belt.

So I loosened the 3 Allen screws, twisted a screw driver in-between the 2 sections and tightened the belt slightly.

No more belt slop (obviously), but better still.... no more drive rumbling sound.

 

I'm also hoping that this fixes the weird delays and non responses I get when I try to fine tune the alignment with the software slew controls.

 

Anyhow, maybe someone else is getting this noise and now knows what to do.

 

Merry Xmas and Happy New Year to you all.

 

Grumpy

[alphatripleplus]

Glad that this fixed it for you.

[Sacred Heart]

Hey Grumpy,  I'm glad that was all it was.

      I just want to tell you something just in case.  My neighbor, bought his CGX about 3 maybe 4 years ago.  Never really used it till recently.  After using it, it made sounds, he adjusted worm block, belts, in Declination side.  Then the mount would start acting crazy, going back and forth in declination.  His problem was the 4 wire connector to the dec motor.  He got a battery charging cable from a local RC hobby shop and soldered it in.  No more problems, noise , dancing, anything.    If that happens to you, take the cover off the dec motor a just wiggle the wire and see if it goes crazy.

                                          Joe

[EFT]

A couple of other things here.  Your mount has the older sprockets where one of them does not have hubs.  That allows the belt to run off the sprocket.  With the belt bunching, you were essentially seeing something that amounts to backlash in a belt-driven system.  Yes, belts do not eliminate backlash which can also be added to by belt teeth that don't perfectly fit the sprockets.  However, the most important things is that both of the problems, runoff and bunching have the same source, the motor gearbox bushings.  If you look at the worm and motor shafts, you will notice that they are not parallel.  This is cause by wear or deformation of the brass bushings in the motor gearbox.  The result of the tilt of the motor shaft is that that belt wants to run off outward on the sprocket without hubs.  This also results in the belt being loose and bunching.  The problem with tightening the belt tension is that it will put even more pressure on the motor gearbox bushings wearing them even worse.  The only way to fix this "permanently" is to install ball bearings in the motor gearbox in place of the upper and lower bushings on the gearbox shaft.   

[moonrider]

A couple of other things here.  Your mount has the older sprockets where one of them does not have hubs.  That allows the belt to run off the sprocket.  With the belt bunching, you were essentially seeing something that amounts to backlash in a belt-driven system.  Yes, belts do not eliminate backlash which can also be added to by belt teeth that don't perfectly fit the sprockets.  However, the most important things is that both of the problems, runoff and bunching have the same source, the motor gearbox bushings.  If you look at the worm and motor shafts, you will notice that they are not parallel.  This is cause by wear or deformation of the brass bushings in the motor gearbox.  The result of the tilt of the motor shaft is that that belt wants to run off outward on the sprocket without hubs.  This also results in the belt being loose and bunching.  The problem with tightening the belt tension is that it will put even more pressure on the motor gearbox bushings wearing them even worse.  The only way to fix this "permanently" is to install ball bearings in the motor gearbox in place of the upper and lower bushings on the gearbox shaft.   

Yep, what Ed says is necessary.