Restoring LX200 Classic

[yuklop]

Hi Everyone,

This post is about restoring and rebuilding a 12'' LX200 classic. I did a load of research and pulled ideas from various parts of the internet and I want to post it all in one place in case others find it useful.

A summary of the mods I did (a more detailed section on each mod follows including how hard it is, how effective, how expensive, and where I got the bits).

The start point was this LX200, which was optically good, but a bit battered around the edges (had been an insurance write off when I purchased it). It also had a dec drive with huge backlash (>99!) and it refused to slew further round than due east.

Summary

1. Stock focusser upgrade

2. OTA deflocking and internal painting

3. OTA and forks painting

4. Serviced the finder scope

5. Replaced all electronics with Onstep

6. Replaced dec and RA bearings

7. polished the brass bubble level!

 

1. Focusser Upgrade

Guide: http://www.skymtn.com/mapug-astronomy/MAPUG/ImgShift.htm

Cost is just a few pounds, it is very easy and a very effective modification. In fact, if I were only to ever do one mod to an LX200 it would be this one.

You need:

2 x Needle roller cage bearings: https://simplybearings.co.uk/shop/p110004/NTA815-Needle-Roller-Cage-Only-0.50x0.9375x0.0781-inch/product_info.html

1 x Thrust washer: https://simplybearings.co.uk/shop/p110209/TRA815-Needle-Roller-Thrust-Washer-0.5x0.9375x0.0312-inch/product_info.html

 

2. OTA deflocking and internal painting

Here is how to take it all apart: http://www.lx200classic.com/files/Gutting your LX200 OTA.pdf

My OTA had awful flocking all over the inside. Put on with tape that was both near impossible to remove and flaking off at the same time. Cost is low, but it is time consuming and tricky, especially since you need to remove the primary mirror before attempting this. It should be fairly effective though as I won't have bits of old flocking hanging off inside the tube.

You need: IPA to help remove adhesive. Elbow grease. Then some chalk board paint into which I mixed a load of carbon black for an extra absorbent and rough non-reflective surface. Then paint that on.

 

3. OTA and forks painting

No guide required for painting. You do need to take it all to bits though. A really good guide for that an the reassembly: http://www.skymtn.com/mapug-astronomy/ragreiner/decfixmajor.html

I painted mine white with black forks. Image at the end! I will say my mount had lots of small areas of corrosion that needed rubbing off first.

 

4. Serviced finderscope

Mine is a skywatcher 9x50 right angle finder. Very easy to take apart. Nice clean with baffles and optical wonder and it is as good as new. Well worth doing.

 

5. Replaced all electronics and motors with Onstep

I was facing tuning the LX200 drives like this: http://www.skymtn.com/mapug-astronomy/ragreiner/decdriveadjust.html or http://www.lx200classic.com/files/Bruce_Johnston_LX200_Drive_Repairs.pdf

Didn't fancy it. So I thought I'd rid myself of the old drives and all the old 1990's electronics at the same time and replace it all with Onstep. Now its done it was definitely the right choice.

https://onstep.groups.io/g/main

I cannot speak highly enough of Howard, Khalid, George and Drew and all the other great people working and helping to allow folks like me to restore an old telescope with Onstep. I'll post a message to the onstep boards on all the details, but essentially I now have a stepper motor driven mount, 2 electric focussers all controlled over WiFi from my phone or tablet. Cost is very low for such a major mod (<£100 in my case). I will likely recover all the money when I sell the old handset and electronics. You will need to be a bit handy with a soldering iron and computer science but the instructions are good and the help available is awesome.

 

6. Replaced Dec and RA bearings

RA: https://www.cloudynights.com/topic/507157-ra-bearing-replacement-and-accessory-cable-management-modifications-for-a-meade-lx-200-gps/

You need one of these:https://www.ebay.co.uk/itm/113994912099 BEARING SIZE:6013 2RS 65MM X 100MM X 18MM and one of these: https://www.ebay.co.uk/itm/360617561146

Dec: http://www.skymtn.com/mapug-astronomy/ragreiner/decfixmajor.html

You need: 2 x roller bearings: https://simplybearings.co.uk/shop/p92349/BA1616ZOH-Imperial-Needle-Roller-Bearing-1x1-1/4x1-inch/product_info.html and a couple of thrust washers. I got mine from ebay: https://www.ebay.co.uk/itm/KOYO-TRA1625-Imperial-Thrust-Washer-1-x-1-9-16-x-1-32/123720798055?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

And to have the mount dec holes accurately bored. This cost me £30 by a bloke with an industrial milling machine my wife found on facebook. My experience was that all the local engineering companies didn't want to know. It is the one job in this whole build I could not do myself. I do own a drill press, but it was not worth messing up the centering. 

 

7. Polished the brass bubble level.

As standard it is painted black. Rub that paint of and it is made from brass. Lovely. Oh, I swapped the old handle on the back for a chunky kitchen drawer handle. Another great little mod!

 

The final result is below. Hopefully may more years of action for this this excellent old LX200 classic with its new lease of life.

[Merlin66]

I used the 12" LX200 for many years, and found the best "improvement" I made was to change the Dec bearings to needle bearings.

Adding  dual focusing motors (Zero Shift and mirror knob) as well as the mirror lock also helped.

 

[billhinge]

2 hours ago, yuklop said:

 

The start point was this LX200, which was optically good, but a bit battered around the edges (had been an insurance write off when I purchased it). It also had a dec drive with huge backlash (>99!) and it refused to slew further round than due east.

 

You can buy insurance write off telescopes ? 🙂

Didn't know that, seriously nice job and good write up!

[ollypenrice]

Lots of really helpful information here. Many thanks. Your scope now looks perfect.

Olly

[yuklop]

Thanks for the comments. 

I had a colleague who had a car crash into his garage knocking this scope for 6. It got a bit dented and insurance wrote it off. He got himself a new 14'' ACF with the proceeds, lucky chap, and I got this one for a good price. This would be risky, but I got to try the scope and check the optics out before I bought it. The dings and dents could all be knocked out!

[kirkster501]

Wow, what a great job and well done.  Much of what you discuss could be applied to other scopes too.