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  #41  
Old 20-02-2010, 07:37 AM
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I got mine from Deep Space products

http://www.deepspaceproducts.com/def..._HyperTune_DVD

It is the same as the one Astro Rubylith sells

http://www.astro-rubylith.com/category.sc?categoryId=5
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  #42  
Old 24-02-2010, 12:09 AM
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Pete,

I probably won't ask this question very cleary so please pardon my stumbling through the wording.

When I hypertuned my first Atlas there was a point in the reassembly where everything but the motors had been installed. The instructions I used directed me to reach into the motor compartment and feel where the worm spur gears protrude into the compartment via the slots in the walls. If I could turn them with my finger tips and thus make that axis slowly move, then supposedly that meant everything was meshed welll. On the other hand if one or both spurs could not be moved with my fingers it supposedly meant the meshes were too tight, and therefor the motors would have difficulty moving them as well.

Did you go through a similar process in appraising the tightness or looseness of your gear meshes after reassembling the mount?

The problem I had was annoying. As I turned the spur with my fingers, it would go smoothly until reaching what felt like a sticky spot. I had to push harder to get past that sticky spot, then it got smooth again until the next one. On the RA axis I had one or two spots, but on the DEC it was more like 4-6.
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  #43  
Old 24-02-2010, 05:59 AM
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Curt,
That looks bad.
Either the worm shaft is bent (that would explain one sticky spot) or the worm is damaged (couple of bumps on threads) or (less likely) you have hard particles/dirt in grease which are now pressed into worm surface.
Is this happening at every position of the worm gear (I know.. you have to turn it 140 times to find out. If yes, at least you know the gear is OK)
Anyway, all this will result in increased periodic error,
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  #44  
Old 24-02-2010, 06:23 AM
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Curt,

I left two (RA and DEC) of the worm shaft caps off (the ones on the side of the mount where the power and hand control connections are as this end of the worm shaft is retained in place by a screw-in ring. I then inserted a small length of plastic tube over the end of the shaft so the tube was protruding out of the mount. You can then turn this either with your fingers (without reaching into the housing) or with an electric drill.

Using this tube to rotate the worm I found the high (tight) point on the worm ring gear (I think pretty much all of these mounts have some degree of run out). I then adjusted the gear mesh at this point. I also found the feel of this adjustment was easier if the mount was somwhat balanced (I extended the counterweight shaft).

Hope this makes sense - if not let me know and I'll post a picture.

Peter
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  #45  
Old 24-02-2010, 07:47 AM
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Ah, yes, the mount MUST be balanced when doing this.
Because, when you rotate the worm against load, the mount will behave more or lees OK (except for increased friction resistance due to pressure on worm threads).
But if you do it in the same direction (where mount wants to go because of unbalance) the mount first tends to stay where it was due to friction. But when the worm touches and pushes the teeth of the gear, the friction will "get free" and the mount will "fall" due to the unbalance until it hits the other side of the teeth, where it will stop (friction again).
And so on. So the balance is paramount here.

Also, I forgot to mention, your "sticky spots" may be due to too much pressure on worm ball bearings, or dirt inside them... or both.
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  #46  
Old 25-02-2010, 08:03 AM
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Ah, I need to leave a cap off as well so I can observe the worm cycle while manually turning the gearing for each axis. Last year when I went through this process I had already installed both caps, so when I turned the spurs manually after reassembling the mount I didn't have a way to see where the worm was rotationally.

Still I'm not sure it could have been the worms that were the problem. My diagnosis was that those sticky spots were problems with the large cogs rather than the worms. If were the worm instead I would have expected A LOT more sticky spots. Here's why - I literally sat there and spun each axis 360 with my finger on the spur. It took a long time for each axis but I wanted to feel where the problems were. If the sticky spot had been a single point on the worm, I should have felt it at regular intervals. Also, I should have felt more than just three or four in a full 360 of each axis.

Does that make sense?

I really appreciate your feedback on this. My new EQ-G arrived today and I'm determined to lick my hypertuning mystery this time around.
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  #47  
Old 25-02-2010, 09:13 AM
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The main reason for leaving the cap off is that you can attach a piece of hollow plastic tubing over the spindle of the worm gear and use this to turn the worm gear rather than getting your hand inside the mount housing to turn the gear attached to the worm gear. Its easier to do and just as sensitive.
One thing that happened to me was that after assembing my EQ6 mount, the dec axis was perfect but I suddenly had a 7-8 sec lag before the ra axis would reverse direction at slowest speed. The reason that I finally found is that there are 2 grub screws on the worm gear that hold the worm and the gear together. One of these was not sitting on the absolute flat point of the worm gear. While testing the backlash etc of both axis - perfect but once I loaded it up with the scope and counterweights it was enough to dislodge the grub screw so that it oscillated on the worm gear giving me the 7-8 sec delay between motor reversals. So if you have NO backlash but get a delay in axis movement this is your probable cause. I had to strip the axis back down again to fix this and then re-adjust all the backlash etc again. About an hour job.
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  #48  
Old 26-02-2010, 01:44 AM
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Allan, thanks for the heads-up. It makes perfect sense what you're describing. I didn't have that exact problem because I obsessed over aligning the flat spots with the set screws. It was tough because you can't see it very well as I remember.
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  #49  
Old 26-02-2010, 08:20 AM
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Quote:
Originally Posted by opticalsupports View Post
Allan, thanks for the heads-up. It makes perfect sense what you're describing. I didn't have that exact problem because I obsessed over aligning the flat spots with the set screws. It was tough because you can't see it very well as I remember.
Curt, I thought that I had also been obsessively careful as I marked it with a "sharpy" to know where the flat was but I must have been just a bit off and with the scope load rocking it back and forth, the screw gradually worked itself loose so that it went from perfect (No backlash or delay in reversing the motors) to a 7-8 sec delay in reversing the motors. Just something to be aware of.
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  #50  
Old 01-09-2010, 10:06 AM
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Peter, do you have any contact details for Doug Dieter, none of the links in the Yahoo spacer thread work, I'd like to contact him to see if he still supplies the Delrin spacer kits.
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  #51  
Old 01-09-2010, 11:50 AM
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Thank you all for the very (to me) important information in this thread. I have the basic EQ6 that I have stripped & tuned the best I could without any part replacements as such. I have these tight spots on the ring gear too. I'm only concerned with the RA axis & it's PE. Does anyone make a better quality ring gear & worm for these mounts? Sorry If I have missed any info. related to this in this thread.
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  #52  
Old 01-09-2010, 04:54 PM
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Phil,

Try this email address:

skygazer at kennaquhair dot com
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  #53  
Old 01-09-2010, 05:03 PM
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John,

You can purchase replacement ring gears and worms from:

http://www.aeroquest-machining.com/index.html

I've also seen references to Gierlinger gears from Germany but don't know the website address. Check out this thread:

http://www.iceinspace.com.au/forum/s...ad.php?t=19091

Last edited by peter_4059; 01-09-2010 at 05:35 PM.
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  #54  
Old 01-09-2010, 05:27 PM
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Just be aware that the main problem with EQ6 is not PE per se.. the real problem are the sudden jumps 1-3arcsec, due to gear transfer.
PE caused by worm is relatively large (~20arcsec pp) but this can be guided out, as it is smooth in most cases.
PE analysis (to determine the cause of the problem) is essential before spending money un-necessarily.
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  #55  
Old 01-09-2010, 07:17 PM
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Quote:
Phil,

Try this email address:

skygazer at kennaquhair dot com
Thanks Peter.
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  #56  
Old 01-09-2010, 09:52 PM
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Thanks Peter & Bojan
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  #57  
Old 04-09-2010, 09:56 PM
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Some of the links on Beevo's stripdown site are not functional I found a more comprehensive alternative here.
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  #58  
Old 29-10-2011, 05:20 AM
Poita (Peter)
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Quote:
Originally Posted by bojan View Post
Just be aware that the main problem with EQ6 is not PE per se.. the real problem are the sudden jumps 1-3arcsec, due to gear transfer.
PE caused by worm is relatively large (~20arcsec pp) but this can be guided out, as it is smooth in most cases.
PE analysis (to determine the cause of the problem) is essential before spending money un-necessarily.
Is there anything that can be done about the gear transfer problem?
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  #59  
Old 29-10-2011, 08:07 AM
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Quote:
Originally Posted by Poita View Post
Is there anything that can be done about the gear transfer problem?
Yes, apart from cleaning or replacing them with high-precision gears (expensive!), you can have a look what I have done about it. However, this was not hyper-tuning - this was modification, so my reply is somewhat OT..
http://www.iceinspace.com.au/forum/s...ht=timing+belt
Many others before me did it (I was just following their example), with good results.

The presented mod still have one gear transfer stage (1:4) but currently I got rid of this one as well, so now the motor drives the timing belt directly.
I only need some free time and nice weather to test it.
The processor h/w & f/w used at the moment are according to Darren's mod presented on his website (http://projects.gbdt.com.au/eq6-1/ , it supports various transfer reduction rates), but my final intention is to use Mel Bartel's software with this, once the mount is permanently set up.

Last edited by bojan; 29-10-2011 at 09:43 AM.
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  #60  
Old 03-11-2011, 06:48 PM
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apart from belt mods we've had some improvement by fitting better constant velocity profile gears. These along with a PierAstro kit (ceramic hybrid bearings all round, steel shims, motor nose bearings, etc) made a huge difference. Lapping the Gerlinger worms was the final touch, about as good as it gets now. The main sorce of grief in these mounts is the worm end float control. I'd like to drill/tap the end covers and fir either a pointed hardened grub screw or a small spherical saphire lens to make a jewelled movement ;-)
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