27 April 2021 at 3:08 pm #574950Charles VinceParticipant
My telescope has developed a fault. On switching on the tube turns continuosly in the Dec axis. I have contacted two dealers about this, both of whom are unable to help. I wondered if anyone else has come across this problem and is there anyone who can carry out a service on this telescope as I would very much like to be able to carry on using it. I am located in Wiltshire.27 April 2021 at 5:07 pm #584127Mr. Martin Paul MobberleyParticipant
This is the standard failure mode of the Classic LX200 and these failures were very common during the 1990s and early 2000s. The problem is that the drive chain on both axes consisted of a ‘Scalextric’ toy car motor (worth about 50 pence in the 1990s) and some tiny plastic gears (plus encoder wheel) which were very fragile. Despite their fragility the first gear spins around at 14,000 rpm on full slew! Many LX200 users, including myself, suffered failures due to this fragile drive chain falling apart. My own LX200 failed on the second night of use on Dec 26th 1997!! Numerous other failures followed over the years until I dismantled it in 2003. When these telescopes were in mass-production the dealers stocked huge numbers of replacement motor/gearbox units. I think I paid for about half a dozen replacement units in the years of failure outside warranty. The dealers told me that they subcontracted a motorbike restoration enthusiast in Essex to do the repairs (!) because they did not have the time! I wrote a BAA paper 12 years ago about my final solution, but it involved a complete remounting of the tube and the subsequent system was only rigid enough for planetary imaging, not deep sky/comet imaging. There is no easy way to solve the problem now, but many people use AWR technology: http://www.awrtech.co.uk/ih/lx-upgr.htm
My BAA paper is here: http://articles.adsabs.harvard.edu//full/2009JBAA..119..183M/0000183.000.html
I have attached a photo of the Classic LX200 motor and gearbox. The whole unit is about the same size as a large matchbox!
Maybe other BAA members have found better solutions for fixing their old LX200s….?
Martin27 April 2021 at 5:19 pm #584128Robin LeadbeaterParticipant
I believe this is commonly because potentiometers on the motor control have become unbalanced and need adjusting. For example as here
There was someone in the UK (Alan Sickling) who used to know all about these. His email was alan (at) sickling(dot)co(dot)uk but this was from over 10 years ago now
Robin27 April 2021 at 6:04 pm #584129Callum PotterKeymaster
My LX200 mount failed but not with the same problem – it would slew on one axis but not move at all on the other.
I, and a friend who does some mechanical telescope work, searched for someone to look at it to repair, but we could not find anyone to look at it.
In the end I had my friend de-fork it, and put a Losmandy doovetail on, so I could mount on a G11.
Callum27 April 2021 at 7:29 pm #584130
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