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Ra stuck on G11 Gemini 1

 

Can anyone please advise, had the 250mm newt on my G11, got to grips with the new camera, managed to align 2 stars for the first time, was having a smashing evening and bam, the RA has jammed up, the motor is going round but nothing is turning, I can turn it manually if I loosen the clutch but on the motor there is nothing, also what can I expect when I start to strip it down, will anything spring loaded fly out?

Thanks
 

Dave,

Do you have a classic G11 Gemini 1? What I mean by this is do you have the straight line drivetrain with the servos and gearboxes hung out in the breeze. The current tucked-in servos change the way things need to happen quite a bit.?

--

Chip Louie Chief Daydreamer Imagination Hardware?

? ?Astropheric Weather Forecast - South Pasadena, CA?
 

If you have a Classic then it is easy to check where the drive power gets lost. My first suggestion is to check the 3-piece Oldham coupler between the gearbox output and the worm gear, this part has several grub screws, 2 per side on the metal parts and a plastic sliding piece between them. The most common issue is loose grub screws on the Oldham coupler which then allows the servo to run but without driving the worm and the plastic piece popping out of the metal parts of the coupler. You can see these by removing the worm cover.??

The other common problem is the gearbox has failed, the mounting of the servo to the gearbox failed allowing the servo motor pinion to lose contact with the gearbox internal gears. I have seen one rare problem where the pinion gear is slipping on the servo motor due to splitting.?

Take a peek and keep us posted.
--

Chip Louie Chief Daydreamer Imagination Hardware?

? ?Astropheric Weather Forecast - South Pasadena, CA?
 

Based on his description it seems to me he has a rough spot in the gear that's making the motor stall. I just finished cleaning my mount and had the same issue, first on the DEC motor, then on the RA motor. If the worm is not centered with the motor shaft it might get stuck at some point in the rotation. In my case it would turn fine for almost the entire time, then at one spot in the DEC/RA rotation it would just stall (maybe when weight change sides)

Add to that the newly added camera to the setup which might have changed balance.?

I'd suggest you to first check if the system is well balanced. Then what i did to find my problem is to loose the worm block far from the motor, and let it run for a few turns to see if the worm is turning centered or if it's wobbling a bit. If it's not, you have to adjust your worm blocks to make it centered with motor, or adjust the position of the block far from motor to give it some more space to turn.

Guilherme


On Mon, Sep 21, 2020 at 3:49 PM Chip Louie <chiplouie@...> wrote:
If you have a Classic then it is easy to check where the drive power gets lost. My first suggestion is to check the 3-piece Oldham coupler between the gearbox output and the worm gear, this part has several grub screws, 2 per side on the metal parts and a plastic sliding piece between them. The most common issue is loose grub screws on the Oldham coupler which then allows the servo to run but without driving the worm and the plastic piece popping out of the metal parts of the coupler. You can see these by removing the worm cover.??

The other common problem is the gearbox has failed, the mounting of the servo to the gearbox failed allowing the servo motor pinion to lose contact with the gearbox internal gears. I have seen one rare problem where the pinion gear is slipping on the servo motor due to splitting.?

Take a peek and keep us posted.
--

Chip Louie Chief Daydreamer Imagination Hardware?

? ?Astropheric Weather Forecast - South Pasadena, CA?
 

Very likely your coupling gave way.? This can happen with the inline couplers. The clamping type. If the worm meshing gets tight with dropping temperature and you have high torque motors they won't stall. The coupler will give on the worm side or gearbox shaft side. Never happened to me with the oldham because they have grub screws. Different system.
 

Hi all, update, the grub screw on the Oldham coupler had come loose, the thread in the hole has gone sloppy and the screw could do with being a bit longer to catch more thread, fortunately there are 2 grub screws on either end of the coupler so I have used the other on for now to get me out of a hole, I want to try and find some longer grub screws.
The Allen key is 1/16 according to its holder, is that the size grub screw I need to order can anyone please advise?

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