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Equipment Discussions >> Mounts

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neilson
professor emeritus


Reged: 08/22/10

Re: Why me? new [Re: WadeH237]
      #5410328 - 09/08/12 03:50 PM

Hi Wade,
I liked everything you just wrote and agree with it. Except that I am in no way expecting any China mount to perform to the same levels as any Astro Physics or losmandy mount. But I do believe that Meade can correct the problems that are keeping this mount from working as advertised, or close to it. And they can do it for the current price. I hope they do. It could bring this company back. I also feel many Astronomy products are very overpriced. That's how all the upper management at companies like Meade make those huge salaries and get all those big bonuses. And I know I could do a better job than them, heck just hire someone for quality inspections would make a huge improvement, and save lots of UPS return shipping costs. How can a company making scientific instruments requiring exacting accuracy not have any kind of quality control. Especially for something made in China.
And I know what you mean about that ACF ota. My 10" LX200ACF's box says LX200R. I am glad they pushed Celestron because my new 9.25 ota is an Edge and I really like it. I just think they should sell this mount for $1,000., and it should reach its advertised ratings and maybe there could be some competition going on. Then others could afford larger telescopes. Instead of this apparent price fixing atmosphere.
neilson


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rmollise
Postmaster
*****

Reged: 07/06/07

Re: Why me? new [Re: neilson]
      #5410349 - 09/08/12 04:07 PM

Astronomy products are NOT overpriced. Quite the opposite. That's part of the problem.

As for the LX80, yes it can be put right. Will Meade put it right? That remains to be seen. They never put the RCX 400 right, alas.


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dmdouglass
professor emeritus


Reged: 12/23/07

Loc: Tempe, AZ
Re: Why me? new [Re: rmollise]
      #5410380 - 09/08/12 04:30 PM Attachment (28 downloads)

Hi Michael...

Neilson alerted me to your post. I watched your video, and listened to an all to familiar sound. And I have read that you identified the problem.

I can show you what is going on... pic below. The motor is NOT mounted using the conventional external(to motor) mount holes, which indeed, are present. The one at center bottom of the motor is NOT accessable, as the populated gear box is in the way. The screws that ARE used, must be put in BEFORE the encoder PC board is inserted (glued?), and are thus also NOT ACCESSABLE.

In my case, the motor was loose. I think mine was damaged from the collapse. Not so sure now. But damaged beyond repair. This condition is NOT REPAIRABLE. And, after studying the situation further, it is also NOT ACCEPTABLE. It your mount experienced this, and was not dropped, bumped, or otherwise "banged"... then it is a weak link, and that will affect all users at some point in time.

Added by Edit: I should state that what has occurred is that one or both of the two small motor attachment screws (see photo) have torn loose from the plastic next to the PC board. If the motor is still "sort of attached", then one screw (and thus the motor) is loose, and can move aroundd, resulting in the "clunking" of the gears, or at times, total non-alignment of the gears (as in no DEC movement).

Edited by dmdouglass (09/08/12 04:38 PM)


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OzAndrewJ
scholastic sledgehammer
*****

Reged: 11/30/10

Re: Why me? new [Re: Whichwayisnorth]
      #5410467 - 09/08/12 05:34 PM

Gday Micheal

Quote:

Yah this was all done in Alt/AZ mode.




I could see that from the video ( unless you were at the pole ).
I was more interested in how it ran altaz with NO load at all.

Quote:

do a drive train. Made sure to only go one way on the arrows. Don't overshoot and go back. Then I did a drive calibration and curious if I should have done it the other way around I repeated the drive training just to be safe.




Calibrate should be done first, as it tweaks the encoder LEDs for best waveform.
However, drive train results can be VERY useful in diagnosing things.
What sort of numbers did you end up with???

Quote:

C)Changing direction the mount would move one way then back the correct way.



That is what i referred to as "retrograde motion".
It is seen ( esp in DEC when polar ) in LX200s and most people seem to reduce it by better lubrication and lighter spring loads on the worm to wormwheel.
There were some good writups on the cause in MAPUG many years ago.
That is partly why i still suspect it has a too strong springload.

Edit
However, after seeing your video, i see it's probably 2 problems running concurrently.
I still reckon the worm is excessively tight, ( to stop it springing out )
The added friction due to this, in conjunction with the bad gear alignment, allows the slipping teeth under load.
As David noted, the way it is designed, you cannot get to the motor holding screws, as one is behind a glued in circuit board, so cant adjust no matter what.
Not a good design feature.

Andrew

Edited by OzAndrewJ (09/08/12 05:59 PM)


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blueman
Photon Catcher
*****

Reged: 07/20/07

Loc: California
Re: Why me? new [Re: dmdouglass]
      #5410473 - 09/08/12 05:36 PM

A very poor design and I doubt that anything less than a compete gutting of the mount and replacing the internal parts with something that works will do.
Blueman
Quote:

Hi Michael...

Neilson alerted me to your post. I watched your video, and listened to an all to familiar sound. And I have read that you identified the problem.

I can show you what is going on... pic below. The motor is NOT mounted using the conventional external(to motor) mount holes, which indeed, are present. The one at center bottom of the motor is NOT accessable, as the populated gear box is in the way. The screws that ARE used, must be put in BEFORE the encoder PC board is inserted (glued?), and are thus also NOT ACCESSABLE.

In my case, the motor was loose. I think mine was damaged from the collapse. Not so sure now. But damaged beyond repair. This condition is NOT REPAIRABLE. And, after studying the situation further, it is also NOT ACCEPTABLE. It your mount experienced this, and was not dropped, bumped, or otherwise "banged"... then it is a weak link, and that will affect all users at some point in time.

Added by Edit: I should state that what has occurred is that one or both of the two small motor attachment screws (see photo) have torn loose from the plastic next to the PC board. If the motor is still "sort of attached", then one screw (and thus the motor) is loose, and can move aroundd, resulting in the "clunking" of the gears, or at times, total non-alignment of the gears (as in no DEC movement).




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OzAndrewJ
scholastic sledgehammer
*****

Reged: 11/30/10

Re: Why me? new [Re: WadeH237]
      #5410486 - 09/08/12 05:43 PM

Re
Quote:

If true, how is the mount supposed to know how to track until you complete two alignment stars? Until then, it doesn't know how it's oriented relative to the sky.




Just for info, the scope uses dead reckoning on the first star.
It "assumes" it was North and level when you started the align procedure, hence it knows where it is "roughly" for the first star. It should start tracking immediately at that point based on the known coords.

Andrew


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edl
professor emeritus


Reged: 06/24/04

Re: Why me? new [Re: OzAndrewJ]
      #5410518 - 09/08/12 06:01 PM

Honestly, is there another mount on the planet that seems to require such TLC?

I mount my OTA on the CPC forks, GM8, Atlas, Quarter Hitch, whatever and it just goes. Maybe I can't do 2 hours of guided imagery (strictly visual), but if I leave for an hour the object is still in the FOV when I return.

My one example of an LX80 couldn't even do that. It's a great engineering project for the brave and curious I guess to make this go, but Meade really has an obligation to their customers to fix this. I read their ads, new the risk, and paid the price of incovenience by returning it. Isn't there another word that starts with "f" for false advertising?
As for the you-get-what-you-pay-for argument, I purchased my GM8 with Gemini 1 level 4 used, $1100.00 shipped across the country. Worked perfect right out of the box, and I was not surprised. It was expected.

Best,
Ed L.


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Whichwayisnorth
Pooh-Bah
*****

Reged: 07/04/11

Loc: Southern California
Re: Why me? new [Re: edl]
      #5410610 - 09/08/12 07:14 PM

I made up a virtual representation of what the gear attached to the motor is doing in relation to its neighbor. Dave may be correct and the screws that attach the motor are loose. From what I am being told the worm gear may be too tight against the ring gear in order to prevent it from jumping out with heavier equipment. This is causing enough resistance/striction that it is forcing the plastic gears to give. Solution would be to adjust the worm to loosen it up to free up the system and see if that will result in slippage. Gives me something to experiment with.

Oh and here is the short video I made showing what it is doing. Edit, wrong link sorry. Here is the right one.

http://youtu.be/1sLIPOjFIC0

Enjoy!

P.S. I am having multiple conversations running here, email and PM concurrently. Sorry if I am convering things thrice.

Edited by Whichwayisnorth (09/08/12 07:21 PM)


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EFT
Vendor - Deep Space Products
*****

Reged: 05/07/07

Loc: Phoenix, AZ
Re: Why me? new [Re: Whichwayisnorth]
      #5410628 - 09/08/12 07:23 PM

The problem is that you can't let up on the pressure of the worm against the wheel because the low angle of the worm teeth will then cause it to skip instead of the transfer gear. That's what Nielson was dealing with.

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Stew57
Carpal Tunnel
*****

Reged: 05/03/09

Loc: Silsbee Texas
Re: Why me? new [Re: EFT]
      #5410635 - 09/08/12 07:26 PM

I hate to say it, but this reminds me of a senior design project that never quite comes together.

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OzAndrewJ
scholastic sledgehammer
*****

Reged: 11/30/10

Re: Why me? new [Re: EFT]
      #5410674 - 09/08/12 07:53 PM

Gday Ed

Quote:

The problem is that you can't let up on the pressure of the worm against the wheel because the low angle of the worm teeth will then cause it to skip instead of the transfer gear. That's what Nielson was dealing with.




Just a thought here, based on not being able to see the mount.
Can the carrier locking mechanism be set such that you have a low sping pressure, but the backing bolt is set such that the worm will easily attempt to disengage, but cannot go far enough to skip teeth?
Its a fiddly setting as the teeth are such low profile, but it may be possible.
This would free up the sliding friction forces in the drive, and hence may make it work better for lighter OTAs. Cant see a solution for heavier loads though.

Andrew


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Whichwayisnorth
Pooh-Bah
*****

Reged: 07/04/11

Loc: Southern California
Re: Why me? new [Re: EFT]
      #5410707 - 09/08/12 08:20 PM

And there is no way to adjust that tension under load. You have to adjust, reassemble, test, disassemble, readjust, reassemble, test and so on. I am about to put my OTA and the counter weights back on it and run it for a bit to see what happens. Stupid clouds are coming in tonight so I am not sure I'll get it outside but I'll try.

The problems that Neilson was having were in Polar mode correct? At this point I am still trying to get this to work in alt/az.

Quote:

The problem is that you can't let up on the pressure of the worm against the wheel because the low angle of the worm teeth will then cause it to skip instead of the transfer gear. That's what Nielson was dealing with.




\


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greju
Carpal Tunnel
*****

Reged: 10/13/05

Re: Why me? new [Re: OzAndrewJ]
      #5410731 - 09/08/12 08:40 PM

I can only assume the LX-80 is on the right? With springs like this and plastic gears it is no wonder this mount acts as it does!

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neilson
professor emeritus


Reged: 08/22/10

Re: Why me? new [Re: OzAndrewJ]
      #5410735 - 09/08/12 08:42 PM

Hi everyone,
On the back of the spring adjustment there is a screw that limits the pressure of the worm on the ring. If you turn it a very little it will release pressure, but you need to grab the ring gear and make sure its doesn't have play in the teeth. The best way to set it is with an amp meter on your power supply. The amp draw when slewing on high speed should be between 0.40amps and 0.50amps. you need to run it until you see the highest reading which will be on the high point of the gear. It will momentarily reach close to .50amps.

Where the spring is is a screw that adjusts how far the worm can disengage. It should be set so the worm can disengage completely but I had my spring pressure all the way for heavy loads and it could never disengauge that far. If you have a light ota its better for the spring to not be too tight but you can adjust it and put it back together to see how it bounces over and over. It can take many times to get it just right because you cant tell unless its together with your ota and weights on.
I found if you have it loaded then wiggle the RA about 1/8" movement is a good setting. but if you have a heavier ota there is no good setting.
here is a pic of the adjustments

I had tried 3 springs but it didnt help it but the middle spring thats discolored is the original one. Yours will only have that one spring. the adjustment that limits how far it disengages is that screw.
Below that is a screw with a washer. I put that washer because the screw was bottoming out when I tried to tighten the spring all the way tight. This screw is the spring pressure screw. If you tighten it then you have to adjust the limit screw behind it. If you don't the motor will drag and there may be damage to the ring gear.
Be careful adjusting this too tight.

neilson

Edited by neilson (09/11/12 08:13 PM)


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OzAndrewJ
scholastic sledgehammer
*****

Reged: 11/30/10

Re: Why me? new [Re: greju]
      #5410741 - 09/08/12 08:47 PM

Gday Greju

Quote:

I can only assume the LX-80 is on the right? With springs like this and plastic gears it is no wonder this mount acts as it does!




Ahh looks can be deceiving.
The piccy on the right is the RA drive on my LX200,
and it tracks very nicely thank you

I can disengage the worm using just the pressure from the tip of my little finger, but when operating, it happily stays in place.

With the LX80, it appears the higher teeth angle used on the worm requires a much stonger spring, hence the added friction effects which seem to be the major problem here.

Andrew


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dmdouglass
professor emeritus


Reged: 12/23/07

Loc: Tempe, AZ
Re: Why me? new [Re: neilson]
      #5410743 - 09/08/12 08:49 PM

Hi Neilson...

I think you are showing him a picture of the RA worm/gear assembly. He is having his problem with the DEC assembly.

Its the same discussion, but the "image" and "access" are different.


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neilson
professor emeritus


Reged: 08/22/10

Re: Why me? new [Re: neilson]
      #5410751 - 09/08/12 08:54 PM Attachment (26 downloads)

Here is my first mount before I tried anything. It was bouncing really bad. It would disengage if you put any pressure on the ota and would skip across the gear until it caught again. My ota almost hit the mount the first time it happened. Thats what mede me adjust the spring tighter. It origonally had 1/4" of movement in RA.

Andrew, on the picture above. The screw on the left reduces that friction
neilson

Edited by neilson (09/08/12 09:08 PM)


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neilson
professor emeritus


Reged: 08/22/10

Re: Why me? new [Re: dmdouglass]
      #5410759 - 09/08/12 09:02 PM Attachment (18 downloads)

Hi everyone,
Ok I thought it was Ra but the block is the same but you cant get a good picture of the adjustments. Here is a picture of the DEC but you will have to look at the other picture to see the adjustments.
neilson


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OzAndrewJ
scholastic sledgehammer
*****

Reged: 11/30/10

Re: Why me? new [Re: neilson]
      #5410778 - 09/08/12 09:24 PM

Gday Neilson

Quote:

Andrew, on the picture above. The screw on the left reduces that friction




Which left would that be
I am pretty sure i understand how it works now.
I see the process as
a) You have to set the ( hidden ) screw on the other side of the carrier
to prevent the worm being totally ground into the wormwheel.
( this type of stop doesnt exist on any of my other mounts )
b) You screw out the upper screw ( the one inside the spring )
c) You use the middle screw to set the spring compression
d) You screw the upper screw back in to prevent the worm teeth from skipping.

However, based on the forces involved, ( ie the fact your original piccy shows the bracket can bend ), i am wondering how useful the upper screw really is when shove gets to shove???

Andrew


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neilson
professor emeritus


Reged: 08/22/10

Re: Why me? new [Re: OzAndrewJ]
      #5410900 - 09/08/12 10:57 PM

Hi Andrew,
You have everything correct. Every time I adjusted it tight I would feel it was perfect and wasn't moving. No play. Then hours later or that night it would seam to be loose again. I lock-tighted the screws. I am pretty sure it was bending. Something would make it loose because when I went back in all the screws were still sealed. But it was easy to move again. I went through this every day.It just wasnt meant to be set that tight.
Like you said before the angle of the worms teeth make it too easy to kick out. I dont think any spring pressure is going to stop it. And if you set it loose and adjust it so it cant kick all the way out, then its going to bounce back and forth just not all the way out with heavier loads.
neilson


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