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Bruce N
member


Reged: 04/01/13

Hard to turn focus knob
      #5921685 - 06/15/13 03:41 AM

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

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Raginar
Post Laureate
*****

Reged: 10/19/10

Loc: Rapid CIty, SD
Re: Hard to turn focus knob new [Re: Bruce N]
      #5921810 - 06/15/13 08:26 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?


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Bruce N
member


Reged: 04/01/13

Re: Hard to turn focus knob new [Re: Raginar]
      #5922236 - 06/15/13 12:55 PM

Shipping bolt? Where is the shipping bolt?

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mtnmedic
Late for dinner
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Reged: 11/09/04

Loc: Antelope, Oregon
Re: Hard to turn focus knob new [Re: Raginar]
      #5938797 - 06/24/13 10:05 PM

Quote:

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.


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mtnmedic
Late for dinner
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Reged: 11/09/04

Loc: Antelope, Oregon
Re: Hard to turn focus knob new [Re: Bruce N]
      #5938811 - 06/24/13 10:16 PM

Quote:

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.


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orion61

*****

Reged: 10/20/07

Loc: Birthplace James T Kirk
Re: Hard to turn focus knob new [Re: mtnmedic]
      #5961087 - 07/08/13 07:22 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.

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P26
Vendor - Peterson Engineering


Reged: 05/02/12

Loc: RI, USA
Re: Hard to turn focus knob new [Re: Bruce N]
      #5961108 - 07/08/13 07:44 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?

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orion61

*****

Reged: 10/20/07

Loc: Birthplace James T Kirk
Re: Hard to turn focus knob new [Re: P26]
      #5962156 - 07/09/13 01:00 PM

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

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P26
Vendor - Peterson Engineering


Reged: 05/02/12

Loc: RI, USA
Re: Hard to turn focus knob new [Re: orion61]
      #5962215 - 07/09/13 01:40 PM

Quote:

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.


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orion61

*****

Reged: 10/20/07

Loc: Birthplace James T Kirk
Re: Hard to turn focus knob new [Re: P26]
      #5963628 - 07/10/13 08:00 AM

Quote:

Quote:

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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