Old Dilapidated LX200

mjeremy (Mike) · #1 03-08-2009, 10:54 PM

I was given an Old (7-8 years I think) Classic LX200 10" with rusty field Tripod and the Accesories Box. Apparently it had sat in a Garden Shed for most of those 7 years and had been damp.

Since I had a day off today I thought I would unpack it and have a look. Turns out I had a major Mould issue and some electrical problems. Thats where I need some help!!

I plugged in the Meade supplied Power Supply - moved the switch on the scope to ON and was greeted by a puff of blue smoke!! Further tinkering - removed the front panel - revealed that one of the small Caps on the power supply board had caught fire! - So maybe a trip to Bintel maybe required to see if I can get a new PS board?

After that great start I decided to have a closer look at the OTA - The Primary and Corrector are covered with nice colonies of white mould - although it seems to like the coatings as it wasn't growing on the inside of the tube.

After 30 mins on the net finding out how to take this thing apart I removed the corrector plate (It has a white orientation mark painted on it - more of this later) and then unscrewed the focusser and removed the Primary - The Red grease used by Meade has to be one of the foulest things I've dealt with recently - apart from the black grease they used on the focusser.

The secondary is also covered in white mould so I unscrewed it from the corrector and removed it from it's housing.

I spent 3 hours this afternoon with Warm water/Kleenex and Isopropyl alcohol very carefully removing the mould and a stubborn coating of dust/grime from the mirrors and the corrector. Unfortunately Meade state you shouldn't clean the Primary - but given the mould I don't really see I had many options - I was carefull and exerted as little pressure as I could whilst trying to float the mould off the mirror.

It's not perfectly clean at this point - but the mould doesn't seem to have done any great damage to the coatings. I have reassembled the scope.

Some questions

1. Having unscrewed the secondary housing from the corrector I am not sure when reassembling whether I have the corrector in the scope the correct way round!!! I am assuming that the orientation mark on the corrector plate would have been painted on the outside of the corrector plate?

2. Are the Primary and Secondarys supposed to be rotationally aligned - I didn't make note of the orientation of the secondary with respect to the corrector plate so I'm wondering if there is anything I can do to get the relative rotational postions of Primary and Secondary back the way they were - or doesn't this matter? I chucked a laser collimator in and I can see that rotating the secondary - I didn't completely tighten it up against the corrector is smearing the red spot into a line and back to a spot (of sorts!!) . Any Suggestions as to how to fix this?

3. The RA worm drive appears loose in it's housing - ie with the RA locked and I try and turn the fork arms I can see the whole worm drive assembly moving up and down - This is producing a large amount of backlash - I'm guessing there is a bolt loose? I havn't worked out how to get in there and check yet - though I'm guessing I csn take the bottom off for a closer look?

The Scope was free so I am not too worried about trying some unorthodox things to get it going again. Seems a pity it was bought for who knows how many thousand dollars 7 years back and has seen first light followed by an eternity in a garden shed. I'd like it to see some life in it's retirement years!!

I've got a Celestron Nexstar 8SE and a 12" Dob so there is no massive hurry in getting the Meade back to working order - but I would like to!!

If anyones got any helpful tips etc please post

Mike

netwolf · #2 03-08-2009, 11:08 PM

Mike,

I am not exper on cleaning a SCT, but I would proabably take it to the experts at Bintel. I dont think the cost is very high, I once enquired on the service and found the quote for a 8" to be very reasonable. Bintel also sell some cleaning liquids that are suitable for this type of job.

One other option to expliore is this stuff
http://www.photoniccleaning.com/
CN forums had a video demo of this from last years NEAF and it was very easy to use, you just spray it on and leave it for a while then peal it off. It seems marketed at the Dob's but i dont see why it would not work on a SCT.

I hope you get the old scope up and running, i hate to see a scope like that sit unused.

rogerg (Roger) · #3 03-08-2009, 11:16 PM

Quote:

Originally Posted by mjeremy

3. The RA worm drive appears loose in it's housing - ie with the RA locked and I try and turn the fork arms I can see the whole worm drive assembly moving up and down - This is producing a large amount of backlash - I'm guessing there is a bolt loose? I havn't worked out how to get in there and check yet - though I'm guessing I csn take the bottom off for a closer look?

There's two allen keys which hold the RA motor in place. You probably just need to tighten them. They should be tight, but when tight the motor should have some spring in it such that you can spring it away from the cog a bit.

BINTEL is your best bet on advice, I think you should take it and have a chat to them, even if you end up doing all the work yourself. Unsure if you'll have luck getting replacement electronics.

Roger.

renormalised (Carl) · #4 04-08-2009, 09:32 AM

That is such a shame, a good scope like that just left to rot in a shed. Makes me wonder about people sometimes, how they treat things like that. Bintel would be your best bet to get this one seen to. Judging by the damage that's been done to it, the service may cost more than usual, but you'll be getting a good scope. One that's far from retiring age

Merlin66 (Ken) · #5 04-08-2009, 05:16 PM

Check out the Yahoo Lx200 group.
Blowing the capacitor is not an unusual occurance; can be easily fixed.
The alignment mark is on the outside surface of the corrector.
Yes, the secondary needs to be rotated to give best alignment to the primary.
BTW there's a capacitor in the hand controller (C5) which should also be replaced ASAP. If this one goes you loose the complete controller with very little hope of finding a replacement!!!! This cripples the whole scope and stops you using it at all!
I have both the 10" and 12" Lx200 and they work 100%
Drop me a PM if you think I can help.

mjeremy (Mike) · #6 08-08-2009, 11:59 PM

Thanks Guys - I think I've got as far as I want to go with the DIY approach. I'm due a bonus from Work soon - so I'm going to drop the scope into Bintel and get a quote on fixing it up.

I'll let you know once it's up and running again - I'm sure it will be a great scope once it's had its share of TLC

Mike

Barrykgerdes · #7 09-08-2009, 09:23 AM

Quote:

Originally Posted by Merlin66

Check out the Yahoo Lx200 group.
Blowing the capacitor is not an unusual occurance; can be easily fixed.

BTW there's a capacitor in the hand controller (C5) which should also be replaced ASAP. If this one goes you loose the complete controller with very little hope of finding a replacement!!!! This cripples the whole scope and stops you using it at all!

The problem with the capacitor in the handbox is now repairable. If you have a handbox that has blown this capacitor and zotted the keypad cable. A replacement keypad is available from Ron Sampson and it is quite easy to fit. I have already rejuvinated three old hand boxes.

Barry