Some observations and points you may like to add to your FAQ notes:

If the problem is only stiffness when balancing in Declination then the circular plate with 2 small holes on top of the dec head can be loosened to achieve this. Nothing to remove and it will have no effect on the scope drive when the head is clamped for slewing and tracking.

The RA axis bearing control ring (under the polar scope as you describe) can be loosened for easier balancing.This shaft does not rotate when the RA axis is clamped as the body goes around the fixed shaft. I could not see whether the ring controlled the end float of the RA head on the clamped shaft. It probably does. A little friction is necessary for damping the drive when tracking so dont make it completely free for balancing.

The circular plate underneath the DEC head is indeed the main thrust control for that axis when tracking/slewing and in my case the bearing was slightly stiff. You do not mention that there is also a lock grub scew on this plate at 90deg to the two pin holes . It has to be aligned with a small cut out in the housing so that you can back it off and retighten with a 1.5mm allen key. Perhaps this is a later change?

I found the best way to investigate the mechanical state of the drive and bearings was to remove each of the drive cogs from the motors, by loosening the grub screws. I then ran each motor with the hand controller buttons and observed that they ran quickly and smoothly both ways to confirm that it was not a control or electrical fault. With the motor cogs removed the worm drive and main bearing can then be seperately checked by finger and thumb on the driven cog. Motion should be smooth, easy and you may feel just a little back lash. It is worth going round 360 deg of the toothed wheel as the worm drive can be tighter/looser in some places. Any adjustment of the worm should be done at the tight spot.

In my case fortunately the RA drive felt good but the DEC drive was tight. I removed the control board and cover as you describe.

On the RA worm at this point it is possible to wipe excess dirty grease away from the worm and apply a small amount of clean grease just on the worm. Turn the worm to spread the grease and remove excess. I also put a spot of thin oil on the end of the RA worm shaft where it is located by a chrome hex nut which controls end float on this shaft – any excess is removed after rotating. Below I explain why!

On the DEC drive I had to do considerably more.The worm assembly removes completely by taking out the 4 cap head screws. The worm adjustment grub screw can be left unmoved. With the worm removed it was ideal to adjust main DEC shaft bearing since the free movement can now be felt exactly. I backed it off a fraction to get a nice buttery feel, but could tell this was not the cause of the problem.

The problem was that the DEC worm itself was tight in its block. Remove the cog and undo the chrome locknut. The exposed threaded sleeve under the nut will screw out from the block and the whole worm shaft can now be removed. There is a thin thrust washer not to lose ! The dirty worm grease had spead every where along the shaft into the bearings. All this was cleaned off and the shaft bearings given a smear of oil.
Reassemble the worm block and set the end play with the thread and locknut to a nice feel with no play.Refit drive cog.The worm only can be greased a little and the block refixed. Fit and bed down the larger cap screws first but not tight. Fit the smaller cap screws tight and check the worm adjustment. If it feels Ok tighten the larger caps and check again. It may get tighter in which case you should loosen all the scews, move the grub scew in 1/8th turn and try again.

What if the problem was on the RA axis ? First try backing off the bearing ring on the shaft. If this does not help I would go the whole hog and remove the motor to get out the worm assembly and clean it completely not just adjust the depth.

In my case I now felt confident that the motors were OK.The main bearings on both shafts were not binding but not loose. The worms did not bind anywhere in 360deg and that the worm axles were not binding. The back lash was similiar on both axes and is 1/16″ at the edge of the worm cog. Any less and I felt binding.

I refittd the motor cogs to align with the worm cogs and refitted the control board and cover.
Connected power and tested the drive and was happy to achieve fast and quiet operation on both axes. Back on with the plastic covers and job done.

All these things can be done inside in a warm clean environment and with simple hand tools.
Even those who are wary of things mechanical could probably take off the plasic covers, remove the motor cogs and have a feel of the mechanical drive, remove excess grease and be happy that the mount is in good shape. It does seem that these mounts are prone to locking up on either axis, perhaps due to dirty grease and rather tight factory settings, and prevention may save a more expensive failure or poor slewing.

best wishes to all users,
regards,
Steve.

I believe that the problem is that I’m not making a network connection between the Starbook-S and my Windows XP laptop. The Starbook-S instruction manual outlines a procedure for registering orbital elements for comets by connecting to a PC so I figured I’d try that capability first to see if I could make a connection according to their instructions. When I entered my IP address in the Internet Explorer address bar I didn’t see the Starbook-S screen that the instructions said would appear; instead my PC stated that no connection to that IP address could be made.

Thanks for replying,
Peter

Thank you,
Peter

Although I am a big supporter of open source, I don’t intend to open source my code for a variety of personal reasons. The code was originally written in VB6 and I am part way through a port to .NET (which is what ASCOM has moved to) but as noted elsewhere, I am making slow progress as I don’t have a strong motivation to do so given the driver meets my needs and the level of donations vs downloads doesn’t add any incentive.

I have downloaded your 4.4. driver and it works fine with the Starkbook S.
I just wonder why it should be impossible to stop the sidereal tracking. The S enables tracking to be set in 20 steps from 0.1x to 2.0x sideral.
Also the autoguider only seems to work on the y-axis. Which makes no sense as I can move both motors in parallel through the S.

It would be worth 100$ if park and autoguiding could be fixed. Or if your driver was open source and I could employ some of my programmers to get it done.

I will move to astrophysics gear next year but will have to stick with the Vixen part until then and want to test new cameras and a roof installed observatory (vibrations etc).

Because your previous comment on Vixen’s interest in computer age astronomy is dead right: The Japanes companies have by and large missed the computerization of machines and are still trapped in their high-precision mechanical age. Sony’s Playstation is proof of this. Also Vixen’s Web Page is stone age like. It’s about time they woke up before people stop buying their mechanical parts. It’s the Kodak effect that has hit the Music and Video industry.

If I was Vixen’s Product Manager for telescopes I’d ensured top notch drivers and a replacement of the S and any other paddle parts through the iPad. That’s how it will be. a small piece of USB connector Interface but otherwise handheld and finger-operated.

So any suggestions how I could help or get to improve the driver myself is welcome.

Otherwise: really admirable how you keep Vixen-Astronomy afloat with your expertise and service – chapeau!

Alex

I am going to buy the Starbook-S which controls the Vixen GP2 Mount. Is your driver compatible with the Startbook-S?

Thanks,
Peter