russdirks
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Reged: 07/06/12
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iOptron SmartEQ Mods and Partial Disassembly
#5487934 - 10/25/12 12:44 AM Attachment (68 downloads)
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Hello all,
Just got the SmartEQ mount from iOptron, upon which I mounted a used NexStar 4GT that I got for cheap. It's my first telescope after being out of the hobby for about 20 years.
Edited by russdirks (10/25/12 12:44 AM)
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russdirks
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Reged: 07/06/12
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Re: iOptron SmartEQ Mods and Partial Disassembly
[Re: russdirks]
#5487940 - 10/25/12 12:47 AM
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The main points of my post are: - How I improved the rigidity of the tripod
- How I addressed the problem of the tripod extensions slipping under weight
- How I got rid of some slop/play in the RA axis
- What those 4 nuts/set screws are for on the outside of the drive case
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russdirks
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Reged: 07/06/12
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Wobbly Tripod
[Re: russdirks]
#5487942 - 10/25/12 12:49 AM Attachment (69 downloads)
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Wobbly Tripod
After reading of others who had done the same, I decided to epoxy the plastic couplings that are at either end of the top tube, to the tube itself. The single screw that is present just doesn't provide enough rigidity. The epoxy made a very significant difference. Before the epoxy, I would have given the tripod a 2 out of 10 for rigidity and strength, considering the kinds of loads it is claiming to be able to handle. After the epoxy, I would give it an 8 out of 10.
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russdirks
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Reged: 07/06/12
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Re: Wobbly Tripod
[Re: russdirks]
#5487943 - 10/25/12 12:49 AM Attachment (62 downloads)
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...
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russdirks
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Reged: 07/06/12
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Re: Wobbly Tripod
[Re: russdirks]
#5487946 - 10/25/12 12:51 AM
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Just a couple of things I found helpful. - I glued the bottom coupler on first, after completely removing the bottom sliding tube. This allowed me to clean excess glue that oozed out into the inside of the coupler. A paper towel soaked in alcohol worked great for that. (Alcohol dissolves epoxy when it is still wet.
- I applied the epoxy to the inside of the coupler, and then inserted the tube. This would push some of the glue further into the coupler, with little left at the end of the coupler, where you want it the most to really lock the coupler onto the tube. So after inserting the tube, I put a glob of epoxy onto the ledge of the coupler and then used a heat gun to warm it (which makes it runny) so it would seep down into the coupler and run nicely around the edge.
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russdirks
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Reged: 07/06/12
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Tripod Extensions Slipping
[Re: russdirks]
#5487948 - 10/25/12 12:55 AM Attachment (61 downloads)
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Tripod Extensions Slipping
Others have reported that the tripod extensions collapse/slip under very little weight. One forum member used a clamp, which I'm sure works great. After looking closely at the tripod, though, I determined that the problem with my tripod is that the thumb screws don't have enough thread on them. The shoulder of the thumb screw contacts the lug on the coupler before you can get any decent pressure on the leg extension. The simple solution was to use a sharp knife to remove a couple of millimeters of plastic off the shoulder of the thumb screw. Now I can put much more pressure on the leg, and it doesn't slip near as much. Ie. it's much better, but still not perfect. Good enough for the kind of weight I will be putting on a tripod like this.
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russdirks
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Reged: 07/06/12
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Too much play in RA axis
[Re: russdirks]
#5487950 - 10/25/12 12:57 AM Attachment (76 downloads)
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Too much play in RA axis
I hadn't noticed it before, with the tripod being so wobbly, but once I got that fixed up, I noticed that there was a fair bit of play in the RA axis, even with the friction lock on as tight as I could get it. I wasn't sure if it was a natural consequence of nylon gears, or whether some of the gears were a bit loose or out of adjustment. Since I had to partially disassemble the mount to deal with some electronic problems I was (and still am) working through with iOptron customer support (who have been great so far), I thought I would dig a little deeper to see where the sloppiness was coming from. First some disassembly pictures for those that might be interested:
The top cover comes off with 4 screws:
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russdirks
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Reged: 07/06/12
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Re: Too much play in RA axis
[Re: russdirks]
#5487951 - 10/25/12 12:58 AM Attachment (75 downloads)
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There are 4 connectors you have to disconnect, then you can set the cover aside:
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russdirks
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Reged: 07/06/12
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Re: Too much play in RA axis
[Re: russdirks]
#5487952 - 10/25/12 12:59 AM Attachment (77 downloads)
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The DEC shaft:
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russdirks
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Reged: 07/06/12
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Re: Too much play in RA axis
[Re: russdirks]
#5487953 - 10/25/12 12:59 AM Attachment (63 downloads)
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Next remove the 4 screws from the bottom. This allows you to remove the entire DEC head, housing and shaft. Be careful … there are thin washers in between the two parts of the housing. They easy to miss and lose.
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russdirks
member
Reged: 07/06/12
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Re: Too much play in RA axis
[Re: russdirks]
#5487954 - 10/25/12 01:00 AM Attachment (67 downloads)
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Pictures with the DEC assembly removed:
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russdirks
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Reged: 07/06/12
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Re: Too much play in RA axis
[Re: russdirks]
#5487955 - 10/25/12 01:01 AM Attachment (57 downloads)
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another:
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russdirks
member
Reged: 07/06/12
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Re: Too much play in RA axis
[Re: russdirks]
#5487957 - 10/25/12 01:01 AM Attachment (67 downloads)
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I started looking closely at the shaft with the RA worm gear on it. At first I thought it was one complete shaft all the way from one side of the case to the other, but then I realized there are 3 pieces: the shaft in the middle with the worm gear, and two short pieces that but against the middle piece from either end.
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russdirks
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Reged: 07/06/12
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Re: Too much play in RA axis
[Re: russdirks]
#5487959 - 10/25/12 01:02 AM Attachment (55 downloads)
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This just shows the locknut and short segment of screw that is used to sandwich the worm gear shaft.
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russdirks
member
Reged: 07/06/12
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Re: Too much play in RA axis
[Re: russdirks]
#5487960 - 10/25/12 01:03 AM Attachment (66 downloads)
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By loosening the locknut, you can either increase or decrease pressure on the worm gear shaft. In my case, a slight increase in pressure removed the excess play I was experiencing. I would caution against tightening too much. I found that only a light pressure is needed to remove excess play.
I found a problem though. I was experimenting with different amounts of pressure on the right hand set screw, and found that after a certain point, increasing pressure began to introduce excess play in the gears. At first I couldn't figure out why, but then I saw it. There is a small triangular brace that is too close to the set screw. (See below). As you tighten the set screw, the threads and outer portion of the set screw comes into contact with that brace, driving the whole assembly away from the main gear, creating excess play. I thought about carving a bit of that brace away, or grinding the tip of the set screw a bit, but in the end found that by putting minimal pressure on the right-hand set screw, and using the left-hand set screw to add a bit more pressure, I could get a setup where there was no discernible play in the gears, so I just left it that way. Not feeling too adventurous I guess.
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russdirks
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Reged: 07/06/12
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Re: Too much play in RA axis
[Re: russdirks]
#5487961 - 10/25/12 01:03 AM Attachment (61 downloads)
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You can see below that the DEC worm gear shaft assembly has the same triangular brace, except it is on the left hand side. I didn't experiment at all with the tension on the DEC set screws, so I don't know if the same kind of interference exists.
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russdirks
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Reged: 07/06/12
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Re: Too much play in RA axis
[Re: russdirks]
#5487963 - 10/25/12 01:04 AM
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So, if you notice any excess play in either axis that you think is coming from the gear assembly, you might want to try loosening the locknuts and checking to see if a little extra pressure cures the problem. The nice thing is you don't have to take anything apart. The adjustments are totally external.
That's all for now.
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*skyguy*
Pooh-Bah
   
Reged: 12/31/08
Loc: Western New York
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Re: iOptron SmartEQ Mods and Partial Disassembly
[Re: russdirks]
#5488313 - 10/25/12 10:17 AM
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Great job with the disassembly instructions and images on your Smarteq mount. I just bought one several weeks ago and it's nice to see how easy it is to adjust the drivetrain. After using small GOTO mounts from Meade and Celestron that had excessive amounts of backlash, I was surprised to see how well the drivetrain "slop" was controlled in my Smarteq. Maybe I "lucked out" with a well adjusted mount!
Thanks for the post ....
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Astronewb
sage
Reged: 09/19/11
Loc: Connecticut
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Re: iOptron SmartEQ Mods and Partial Disassembly
[Re: *skyguy*]
#5489530 - 10/25/12 11:56 PM
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Very nice thread, thanks for all the images and explanations, it's very useful. Oh, dont forget to get a 5mm/25mm cap screw or knob for your top mounting plate..I see you have a hole, mine didn't have a set screw in it, had to install a cap screw to remove all the vertical play it caused with an OTA in place.
Clear skies,
Paul
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russdirks
member
Reged: 07/06/12
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Re: iOptron SmartEQ Mods and Partial Disassembly
[Re: Astronewb]
#5489586 - 10/26/12 12:51 AM
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Just picked up one today, actually! I saw your thread over on the other astronomy site.
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