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Hard to turn focus knob

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#1 Bruce N

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Posted 15 June 2013 - 02:41 AM

The focusing knob of my new LX90 is fairly hard to turn. Is this normal?

#2 Raginar

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Posted 15 June 2013 - 07:26 AM

Try cranking it in and out 5-10x. Sometimes during shipping the grease settles and needs to be redistributed.

You did take out the shipping bolt right?

#3 Bruce N

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Posted 15 June 2013 - 11:55 AM

Shipping bolt? Where is the shipping bolt?

#4 mtnmedic

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Posted 24 June 2013 - 09:05 PM

Try cranking it in and out 5-10x. Sometimes during shipping the grease settles and needs to be redistributed.

You did take out the shipping bolt right?


I thought the LX90 didn't come with a mirror lock or shipping bolt.

#5 mtnmedic

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Posted 24 June 2013 - 09:16 PM

The focusing knob of my new LX90 is fairly hard to turn. Is this normal?


Raginar does provide one simple solution, which may be all you need. Sometimes the grease in the mirror housing tends to stiffen or accumulate in a sport or two after a while. The suggestion I was given some time ago was to level the scope so the OTA (tube) is parallel to the table/floor (45 degrees) and turn the focusing knob all the way one direction until it stops, then all the way the other direction until it stops, repeating the process several times. This moves the mirror back and forth, thus distributing the grease more evenly across the length of the mirror housing. After a while you should feel the focus knob loosen up a bit.

#6 orion61

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Posted 08 July 2013 - 06:22 PM

On the older LX-200's the focuser knob was screwed onto the focuser shaft. It can be screwed on too tightly then the Allen set screw lockes it, Try to loosen the allen set screw and unscrew the focus knob 1/4 turn. Too much will cause play or focus creep.

#7 P26

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Posted 08 July 2013 - 06:44 PM

No, it is not normal. Does the knob bind after half a turn and then go loose or is it binding all the way through a full turn?

#8 orion61

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Posted 09 July 2013 - 12:00 PM

You don't think he has the mirror lock ingaged do you???

#9 P26

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Posted 09 July 2013 - 12:40 PM

You don't think he has the mirror lock ingaged do you???

Nope. There's no mirror lock on the LX90. But the focus mechanism may have been installed off axis at the factory. Best test is to remove the 3 screws securing the focuser to the backplate, fully extend the focusing rod, and manually push the mirror up and down the baffle tube. If the mirror moves freely the problem was with the focuser.

#10 orion61

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Posted 10 July 2013 - 07:00 AM

You don't think he has the mirror lock ingaged do you???

Nope. There's no mirror lock on the LX90. But the focus mechanism may have been installed off axis at the factory. Best test is to remove the 3 screws securing the focuser to the backplate, fully extend the focusing rod, and manually push the mirror up and down the baffle tube. If the mirror moves freely the problem was with the focuser.

Very good troubleshooting tip, shouldn't hurt Warranty, just be warned try to not let the mirror turn or have the focus rod tip at an outward angle. There isn't a lock on the focus rod and the mirror mount! it can slip off.
Pull the mirror sreeight down and look in you will see what I mean.
Remember to do this after screwing the focuser CCW all the way.






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