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Old 28-04-2020, 11:41 PM
sharkbite
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Lx90 alt play

Hi folks...

What with the rain due this weekend I thought I might get into some maintenance.

My lx90 has some play in the alt axis which I thought I might look at fixing.

When I lock the alt axis I can move the ota about half a degree up and down
According to the setting circle on the fork.

My question, before I start opening it up for surgery, is:

Is this normal?

Ie how much play should there be before correction is necessary?

Its not causing any goto or tracking issues ...
Especially for visual....

I do take the odd photo with it so fixing might improve that...

Just wondering if anybody knows how much play is normal?

Cheers,
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  #2  
Old 29-04-2020, 01:12 PM
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iborg (Philip)
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Hi



I have the 8" LX90, I think there is virtually no play in Alt or DEC. I'll confirm tonight.
I think the worm may be adjusted, and I think it is fairly accessible, my guess would be that has come loose over time. Hopefully it hasn't too badly.

I found that the DEC knob sometimes came loose as the night became cooler, so I fitted an ez-clutch kit from Peterson Engineering (link below), no issue since.
Philip



https://petersonengineering.com/ez-clutch/
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Old 29-04-2020, 02:29 PM
sharkbite
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Thanks Philip...

Thanks for the link...it showed me just how easy it is to remove the clutch mech,
Giving visual access to the worm gear.

Mine looks to be in good condition overall...
But as you say....the worm carriage itself has come loose...
And moves when the main gear does.
The gears look like they mesh realm well...so its not that(phew)

I'll be taking the cover off and fixing this on the weekend.

Cheers,
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Old 29-04-2020, 03:43 PM
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iborg (Philip)
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Hi


I'm glad it looks like an easy fix.


Have fun
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Old 02-05-2020, 06:11 PM
sharkbite
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Post surgery report....

Looking for more info on the Peterson kit I found this:

http://www.thenakedastronomer.com/pa...p#.Xq0pw8YRXm8

Which has really good instructions on the teardown procedure.

I had to tighten one of the bolts holding the worm train, and a small amount of end float on the worm itself. The only play is now in the meshing of the worm and the spur gear so hopefully after I also re trained the drives it should track a bit better.

The nice surprise was that it looks like the previous owner had installed a Peterson kit!

Thanks again Philip for pointing me in the right direction!
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Old 03-05-2020, 09:21 AM
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iborg (Philip)
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Hi
Glad its all fixed.Have fun
Philip
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