Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Meade 10" LX200 GPS SMT Focus Lock Not Locking

  • Please log in to reply
3 replies to this topic

#1 Tom Duncan

Tom Duncan

    Apollo

  • *****
  • Vendors
  • topic starter
  • Posts: 1408
  • Joined: 11 Nov 2008
  • Loc: Chico, CA

Posted 16 October 2019 - 08:41 PM

Recently got a 10" Meade LX200 GPS SMT and find the focus lock doesn't really work. Firstly it's difficult to turn, at some points needing two sets of fingers to do so. Secondly it never really locks the mirror though the focus knob gets a bit harder to turn. I've had a couple of these scopes before and the lock worked fine, easy movement of the knob until some increased resistance is felt which locked the mirror solid. 

 

Any ideas? Not keen on the idea of removing the mirror to get at the mechanism but I will if I have to (instructions with photos or a video would make me feel more confident!).

 

Thanks

 

Tom Duncan 



#2 OzAndrewJ

OzAndrewJ

    Mercury-Atlas

  • *****
  • Posts: 2944
  • Joined: 30 Nov 2010

Posted 16 October 2019 - 09:07 PM

Gday Tom

There are several sites that cover it but the mirror lock only clamps the rear end of the sled to the baffle tube using a tapered collet. If the front of the sled still has a lot of slop, the mirror will still shift a bit.

Some people in the past found they couldnt lock the mirror properly as the collet, when compressed, was still a bit too large, and to fix it they filed out the slots in the collet. Simple enough but requires full disassy

several examples ( not sure how many variations Meade have put out, but they will all be similar )

http://www.jemartool...Lock Repair.htm

https://www.cloudyni...00-mirror-lock/

http://www.centaurus...echanism-repair

 

 

Andrew Johansen Melbourne Australia



#3 MikeBY

MikeBY

    Sputnik

  • -----
  • Posts: 45
  • Joined: 28 Aug 2019
  • Loc: Huntington Beach, CA

Posted 17 October 2019 - 01:02 AM

This link below is the current link to the Peterson site with a procedure to address a common lock problem with the LX200gps. A good description of how the lock assembly works, and a procedure for how to repair it from the back if you have the problem they describe.
Best note the warning about turning the internal gear CCW.

You should be able to turn the lock CW to a stop, and it should turn freely well before then. It may be a lot of turns. I agree once it starts to get resistance it should lock the mirror within a couple of turns. Don't over tighten! It doesn't eliminate mirror shift if the focus knob is moved with the sled locked, but in that case you'll feel resistance on the focuser and should STOP and unlock the mirror.

Beware of a tight focus knob. Its possible to bend the focus rod by forcing it against a locked mirror sled.

https://petersonengi...irror-lock-fix/

Hope you can fix it from the back. Full disassembly is something to avoid if at all possible.

#4 Tom Duncan

Tom Duncan

    Apollo

  • *****
  • Vendors
  • topic starter
  • Posts: 1408
  • Joined: 11 Nov 2008
  • Loc: Chico, CA

Posted 17 October 2019 - 01:37 PM

Thanks all, appreciate the info. 

 

Tom




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics