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My new (to me) toy, 10" LX200 Classic

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#1 macona

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Posted 07 June 2011 - 03:11 AM

A friend back east (im on the west coast) had a scope that he no longer used so he sold it to me. 10" f10 Meade LX200, about 2000 vintage. It came with its base accessories, the diagonal, finder scope, and the 26mm eyepiece. It also came with Meade 8-24mm zoom and a scopetronix 15mm plossl eypiece, True Technology 1.25" flip mirror/filter holder with LRGB and IR-cut filters, a Tele Vue 2.5x barlow, and an Astroscan 2000.

The scope is in real nice shape. Was a bit dusty from sitting. Cleaned up well. When my friend went to plug it in before shipping it something went pop inside. Took the boards out tonight and found a blown shorted tantalum. Replaced that and the main fuse and brought it back to life.

The tripod did get damaged in shipping. Tried to tig weld it back up but it dont look so good. I have a massive old Bogen/Manfrotto 3061 tripod that will work just fine once I machine an adapter plate.

Of course by the time I got the old tripod welded up the clouds rolled in...

Paid $1000 shipped, so even with the bad tripod I am still very happy!

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Meade LX200 Classic 10" Schmidt Cassegrain Telescope by macona, on Flickr

#2 nitegeezer

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Posted 07 June 2011 - 03:23 AM

I see you joined CN just recently, so welcome aboard!!

Before you power the scope up again, you might want to replace all of the caps, rather than just the one that shorted. As I understand, with that vintage scope, this is a common problem, but some of the caps do serious damage when they blow. It sounds like you got a nice warning shot, so take full advantage of it and that scope will be very enjoyable for years.

#3 sgorton99

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Posted 07 June 2011 - 06:36 AM

Very nice. Looking forward to your first light report!

#4 jmiele

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Posted 07 June 2011 - 10:01 AM

I nice setup. That is a great pice. Welcome and enjoy it.. Joe

#5 macona

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Posted 07 June 2011 - 10:22 AM

Tantalum capacitors do not age or deform like electrolytics do so there is no issue with that and the logic board is mostly tantalums. The cap that blew is on the 18v rail to the 5v regulator and was only rated 25v. A little close for comfort in my opinion since it runs off an unregulated power supply. Should have been a 35v cap, which it is now.

I used to do electronic service and repair and I can count the fail tantalum on one hand.

Hopefully I will get a break in the clouds later this week.

#6 nitegeezer

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Posted 07 June 2011 - 10:42 AM

Tantalum capacitors do not age or deform like electrolytics do so there is no issue with that and the logic board is mostly tantalums. The cap that blew is on the 18v rail to the 5v regulator and was only rated 25v. A little close for comfort in my opinion since it runs off an unregulated power supply. Should have been a 35v cap, which it is now.

I used to do electronic service and repair and I can count the fail tantalum on one hand.

Hopefully I will get a break in the clouds later this week.


I am a retired electrical engineer, and normally I would agree with you on the tantalum caps, but too many people have had problems to neglect it. The failure rate may be high for any number of reasons. Scroll down and look at picture in third post as an example. If you want to ignore the warning, that is up to you, but this is not a one of a kind failure.

Good Luck

#7 macona

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Posted 07 June 2011 - 12:50 PM

Thanks for the link. I will look through the schematic and see which ones have 18v running to them and replace them. Looks like that cap there was on the high side of the voltage regulator as well.

#8 Geo.

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Posted 07 June 2011 - 02:25 PM

For whatever reason the tants in the Classic LX200s do fail. Some Minoltas SLRs of the same period have the same problem. Probably a bad supplier. Samsung had a bad run of LCD TVs a year or so ago after using caps from a Malaysian low bidder. Turns out the supplier fraudulently misrepresented the specs. Cost Samsung a lot for a small, but illusory savings.

#9 Geo.

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Posted 07 June 2011 - 02:29 PM

BTW, what part of the tripod was damaged? Welding cast alloy is really difficult.

#10 macona

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Posted 07 June 2011 - 05:27 PM

I did find a site where they list the ones that need to be replaced. I will do that tonight. Also thinking of replacing the 7805 with a little DC/DC converter. More efficient, less heat. Or is the hand control supposed to do double duty as a hand warmer?

George. one of the leg ears broke off. I did successfully weld it back up, but the tripod is in such poor condition that I dont know if I will bother using it. It was stored outside.

Welding that was nothing compared to welding up a broken bearing bracket on my cnc mill. Years of being soaked in way lube. Yech...

#11 macona

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Posted 08 June 2011 - 10:02 AM

You guys were right. Popped open the hand control and the input cap had a crack and two little blobs of solder sticking out like mickey mouse ears. Replaced that one and the one on the power board as well.

#12 nitegeezer

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Posted 08 June 2011 - 11:17 AM

I am glad you looked into it more. Now that scope should give you years of great viewing, I just hope your weather is cooperating better than mine is!!

#13 GeneT

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Posted 08 June 2011 - 05:09 PM

Looks to be in great shape for an 11 year old telescope.

#14 cavefrog

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Posted 11 June 2011 - 12:24 AM

glad I read this... good info I have been looking for. thanks guys! :jump:

Theo

#15 Geo.

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Posted 11 June 2011 - 11:25 AM

I did find a site where they list the ones that need to be replaced. I will do that tonight. Also thinking of replacing the 7805 with a little DC/DC converter. More efficient, less heat. Or is the hand control supposed to do double duty as a hand warmer?


Well, in less fair climes the 7805 has been known to keep the LCD from no longer acting like a liquid.

George. one of the leg ears broke off. I did successfully weld it back up, but the tripod is in such poor condition that I dont know if I will bother using it. It was stored outside.


The LX tripod is a good design, but like most tripods makes use of brittle cast alloy parts. Also the leg tubing appears to be not much more than chrome plated exhaust pipe. Unless well cared for they rust easily.

I recently swapped a Nexstar 8i mount for a dead Nexstar 8 and a dead LX50 mount. Got the Nexstar working, but the LX50 is probably worth 70 cents a pound. However, the tripod is very nice. PM me if you are interested.

#16 macona

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Posted 12 June 2011 - 02:16 AM

Finally got some clear sky tonight. Looks like the scope is still very well collimated even after shipping. GOTO seems to be working fine. Definitely need to get a micro adjuster of some sort.

Here's a couple pics shot with my 60D. Not great, not terrible. Moon was pretty bright tonight before the clouds came in again.

Posted Image
IMG_0504_DxO by macona, on Flickr

Posted Image
IMG_0512 by macona, on Flickr

#17 budman1961

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Posted 12 June 2011 - 10:59 AM

You and I are sooo similar! I picked up the near-twin of your LX200 10" (my version is a f 6.3 wide field). I have done everything including the Peterson Engineering fix for taking the slop out of the rear focuser, with modest succcess. I picked up a Crayford focuser, heres the link: Crayford focuser Best money spent on my LX to date.

Fantastic images!

Andy

#18 budman1961

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Posted 12 June 2011 - 11:16 AM

Here is a photo of the OPT Crayford-type focuser installed. Im currently alt/az, the focuser does clear the bottom of the fork when aimed at the zenith.

Andy

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#19 macona

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Posted 12 June 2011 - 08:54 PM

I think I am going to get the Moonlight focuser. Get rid of that light bottleneck in front of the focuser and give me a place to install the field reducer.






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