Help! Encoder code wheel/grub screw on CGEM motors
Posted 21 October 2012 - 03:13 AM
I used "Get axis positions" in the Utilities menu to verify that both motor encoders were losing a huge number of ticks.
I was able to resolve this by spacing the encoder wheels very close to the photodetectors.
However, I busted the RA grub screw in the process. I recall some other folks have had this same problem.
(1) what is the size of the grub screw? M2?
(2) where can I buy a replacement encoder wheel? anybody know the part number?
As an aside, I've always hated this CGEM, both for its immense bulk and its completely unreliable operation. Many times I questioned my sanity because I couldn't get it to work properly.
But now I know why it has been behaving the way it has, and I'm actually hoping I will now get the great CGEM / CG-5 experience that lots of folks keep talking about.
Posted 21 October 2012 - 02:49 PM
Posted 21 October 2012 - 04:07 PM
Since, I don`t know if its the same encoder (just speculating), I`d suggest you post on the CGEM Yahoo user`s group and ask if anyone over there knows.
Here`s the link to the replacement motor on the Celestron website:
(while the link and page don`t state CG5, the part number on the parts page that links to this page refers to it as Item: CG5-FOO-2)
Hope this is some what helpful.
Best of Luck.
P.S. I remain in a constant love-hate relationship with my CGEM. It`s an awesome GOTO scope but wish I had chosen something entirely different for imaging.
Posted 21 October 2012 - 09:31 PM
To clarify, my encoder is not busted. But I damaged the grub screw on the code wheel when torquing it down, so I will probably damage the wheel if ever I try to remove the screw to re-space it (not that I would need to).
The newer Celestron motors use an E4P encoder (with aluminum push-on code wheel instead of the glass wheel on the E4). I can buy the entire assembly from US Digital and plonk it on the existing motor, and avoid paying an outrageous price for the Celestron motors.
But for now I just want the grub screw replacement (and a new wheel if I end up destroying the old one when I remove the busted grub screw).