EQ6 belt drive modification

[George]

Hi Neil,

I found putting a flat bladed screwdriver between the motor and body casting and twisting until it "felt right", keeping it there until the socket head bolts are tight worked.

Exactly how I adjust mine, you can get quite a feel for doing it this way.

[fwm891]

I think the belt tension needs to be fairly high as unlike a bike chain where the load is always in one direction our belts must respond in both directions without taking up any slack - which appears like backlash from the previous gear system.

...i didn't try twisting the flat screwdriver i may give that a go. I was levering it against the lower part of the stepper. It's quite good at the moment but i am finding it difficult to judge between the mesh adjustment and tension in the belt. I still have slight play in the Axis.

[ncjunk]

Thats got it a bit tighter thanks...now I am going to undo it all and recheck the meshing to see if that little bit of play can disappear.

Theres going to be a week of poor weather so I am going to do now adjust the RA so that I can turn it by hand with minimal backlash then do the belt tension.

[jimao22]

I did it !

The result, here:

[malc-c]

I did it !

The result, here:

You might like to read through this thread again... I'm sure Chris has stated that if you are using the handset then the tracking rate will be out as the factory gear ration is something quirky like 3.94:1 or something similar. Therefore these mods only work correctly when using EQmod which has been set to match the correct ratio for the pulleys used (4:1 being used for the pulleys on the EQ6 in this thread)

[chrisshillito]

I think he is just using the synscan to show how quiet the slew is.

I've now completed my own belt mod - just need to get the mount installed back into the observatory. I'll then take a look at making that device that will trick the handset into working correctly.

[jimao22]

I was sure someone will tell that...

Chris was right, it was just to demonstrate how it works, it was late at night and I was to lazy to install the computer and make all the connections.

Thrust me, I understood perfectly how everything it function:downtown:.

If you read carefully the thread, you'll see that I asked Chris about gear ratios and the numbers inside EQMOD settings.

When I will have data for this, I will post some PEC analysis to see the difference.

No offence.

[malc-c]

Apologies...

[chrisshillito]

I've posted up notes from my own belt mod experiences here:

http://stargazerslounge.com/diy-astronomer/166959-eq6pro-belt-mod-notes.html#post2063903

Chris

[ncjunk]

Very good write up Chris,

You're patent pending belt adjusting device looks perfect for the Dec but how is it on the RA as the RA mounting points for the motor aren't as large as on the dec and therefore the RA wobbles more when the screws are loose making it more difficult to use the top of the motor as a lever point for applying tension to the belt. (suppose the answer is do the screws up more....but with a screwdriver it was easier applying the force to the base of the motor on the RA)

I would say even with a magnetic screwdriver use a dab of grease as the small washer can still fall off, as happened to me, requiring the RA to be losened....luckily mine fell out when i opened up the ra slightly.

One other word of caution is the belt can rub which causes bits to be ground off and fall into the RA.

Very good though.

[astromerlin]

Great thread this, I plan to do mine sometime next year. About the rubbing belt situ, Would it not be prudent to make up some end cheeks epoxied to the larger pully so the belt is guided on the pulley. With both pullys guiding the belt it will be less likely to move off if there is a small difference in parallel alignment of wormshaft and stepper.

[ncjunk]

The smaller pully does guide the belt somewhat but the problem is there is a margin of error as to where you position it on the Motor shaft. This can mean the belt is rubbing on the body of the motor. I had to move it down the shaft a little bit.

As Chris says in his overview it is difficult to see how the belt is performing, so you have to listen out for any tell tale rubbing sounds and adjust accordingly. It would be nice to drill a couple of viewing holes in the mount to be able to look side on at the belt and motor shaft.

[chrisshillito]

Very good write up Chris,

You're patent pending belt adjusting device looks perfect for the Dec but how is it on the RA as the RA mounting points for the motor aren't as large as on the dec and therefore the RA wobbles more when the screws are loose making it more difficult to use the top of the motor as a lever point for applying tension to the belt. (suppose the answer is do the screws up more....but with a screwdriver it was easier applying the force to the base of the motor on the RA)

I know what you mean about the wobble though - it seems a little stingy to only provide two support points for what is after all the very heart of the mount. The tensioner worked ok for me on the RA axis - if it helps you can always use the screwdriver approach to take up the slack then tighten the bolts so they just holds prior to slipping in the tensioner to apply the final fine adjustment.

Chris

[fwm891]

I've posted up notes from my own belt mod experiences here:

http://stargazerslounge.com/diy-astronomer/166959-eq6pro-belt-mod-notes.html#post2063903

Chris

Nice write-up Chris,

Have you done a recording of your drive yet?

I think I may have to get a second 12T pulley and re-do my RA. Though I may try activating PEC first to see how much error I can remove with that.

I'm getting small regular peaks which PEC will remove quite easily but I get sudden random peaks running right off the PHD graph screen to top or bottom.

Having machined your pulleys I hope your not getting the same results.

Francis

[chrisshillito]

Nice write-up Chris,

Have you done a recording of your drive yet?

I think I may have to get a second 12T pulley and re-do my RA. Though I may try activating PEC first to see how much error I can remove with that.

I'm getting small regular peaks which PEC will remove quite easily but I get sudden random peaks running right off the PHD graph screen to top or bottom.

Having machined your pulleys I hope your not getting the same results.

Francis

Hi Francis,

Yes, I've posted my initial pe recording on the other thread. Nothing particularly worrying in the raw data - certainly no unexplained spikes. I used perecorder with a webcam rather than PHD.

Chris.

[fwm891]

Thanks Chris - I have a webcam so I think a download of PE recording and try again.

At the moment I don't know if its mechanical (me) or PHD that's causing the spikes. They seem too randomly spaced for a mechanical issue, my polar alignment seems good so when this wind, rain, snow, hail.... dies down I'll give it another go

Thanks

Francis

[tedscott]

Looks like the firmware may have been hacked to account for a change in the gear ratios. See the last sentence in the penultimate paragraph here:

Stepper Motor Replacement Parts EQ5 HEQ5 EQ6 Pro Atlas Sirius Telescope Mounts - Astronomy Forums | Telescope Forums & Reviews | Astronomy Community

I can't find any other reference to it being done on-line though.

James

Hi. I'm a new member (in Germany at present) and have been considering a mod of this nature - Google found me this forum and thread. Very informative - many thanks to all the posters. I was wondering if this is the source code that you are refering to - found on the Sky Watcher home page (Canadian): skywatcher - SkyWatcher Api - Google Project Hosting I admit - I know zap about computer code. Perhaps you've already seen this - if so, apologies for my intrusion Ted Scott

[jackrussell0232]

Gents,

New to this forum, so let me start by saying hello and thank you to all those who have posted some really useful gen on here.

Just wanted to let you know that I have just finished belt-modding my EQ6 and have posted some PE traces on my new site. If I hadn't messed up my RA worm during the mod, I think I would have been finished much sooner. As it is, it's fitted now, while I wait for an aeroquest worm. In spite of the short nights and cloudy skies I think I've made a good case for the mod.

Feel free to have a look at the EQ6 mod page on my site and pass comment.

Thanks again,

Jack

http://www.alphageek.co.uk

[kookoo_gr]

how did you painted your mout? it's awesome

[jackrussell0232]

Yes, I like the look too. I actually had no choice, because in milling the bulges flat, I took a few too many gouges out of the case, so I had to fill it with car body filler and paint it. This was the longest bit of the whole project.

The paint is some I had left from doing my motorbike mirrors. But did prime before and lacquer afterwards.

Glad you like it.

[philming]

Hi all !

I recently purchased a Lacerta OAG at Teleskop Austria. Since I'm a new client, I went around and watched the mount accessories they had.

And hey, what did I find ?

http://www.teleskop-austria.at/shop/index.php?lng=eng&m=2&kod=sbau-bor-das-6p&skod=%2017&om=Mounts

I wrote them an email to find out if this mod did change the way the Synscan HC was acting.

And apparently not. With this kit you can keep on using the HC just like before, without having to go through the EQmod routine...

[chrisshillito]

I wrote them an email to find out if this mod did change the way the Synscan HC was acting.

And apparently not. With this kit you can keep on using the HC just like before, without having to go through the EQmod routine...

EQMOD is only essential if your belt mod, or indeed gear mod, changes the gearing ratio. I assume this kit must therefore be using 47 and 12 toothed pulleys to keep to the original ratio.

The advantage of a change of gearing to a 4:1 ratio compared with the standard 47:12 ratio is that PE produced responds better to PEC.

Chris

[r3i]

Hi all !

I recently purchased a Lacerta OAG at Teleskop Austria. Since I'm a new client, I went around and watched the mount accessories they had.

And hey, what did I find ?

http://www.teleskop-...d= 17&om=Mounts

I wrote them an email to find out if this mod did change the way the Synscan HC was acting.

And apparently not. With this kit you can keep on using the HC just like before, without having to go through the EQmod routine...

That's an interesting find - it's just the price tag of €129 made me shudder slightly

[malc-c]

Hi all !

I recently purchased a Lacerta OAG at Teleskop Austria. Since I'm a new client, I went around and watched the mount accessories they had.

And hey, what did I find ?

http://www.teleskop-...d= 17&om=Mounts

I wrote them an email to find out if this mod did change the way the Synscan HC was acting.

And apparently not. With this kit you can keep on using the HC just like before, without having to go through the EQmod routine...

Interesting find, and the fact it still maintains the default ratio. My only concern when I was developing my HEQ5 belt conversion was the clearance of the pulleys required a spacer between the housing and cover plate which seems to be omitted from that kit. The only way to make it work without the spacer would be to have very thin pulleys and matching belts, which would be more liable to slipping off if alignment isn't spot on. As for the cost, that's about right, unless they do a large machining run which is doubtful given how specialized these conversions are.

[Gina]

The guiding certainly would seem to be improved by this mod though in my case I wonder if the mount is the culprit in poorer PHD graphs. There's certainly backlash - I can move the mount a noticeable amount by hand in each axis but by deliberately using a slightly unbalanced setup I think this should be overcome. The noise doesn't bother me now I've got used to it and know it's normal. I guess I should record the PE and see if it's bad enough to warrant fiddling with the mount. I may get better guiding when I get to test my new (to me) MN190 with OAG as that would rule out any movement between main and guide scopes. It could be worse, of course, for other reasons. Anyway, mount mods won't be any time yet - too many other things to do.

One thing though could you people who have modded the NEQ6 please tell me how long it took and how long your mount was out of action? Thank you

I need to have words with motionco about belt lengths as twice now the belts they sent were not the length I ordered. The labels were for what I ordered but the belts in the bag were different with a note on the label, hand written saying "MARKED BY LENGTH" eg. this photo shows a 75 tooth belt I ordered with the actual belt being 60 teeth.

Edited April 10, 2013 by Gina