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Newbie question about Meade Classic LX-200

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#1 Jerry238

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Posted 11 May 2011 - 11:13 AM

Hi, Just received my new (used) tele and have a couple of very basic questions. It came without a power supply. It says 18 Volt on the electronics box, but from the internet I get that alot of people sell and use 12V adapters with this scope. Is this OK? It is missing the spreader in between the tripod legs. Is seems that this is necessary to actually tighten the the scope to the tripod. Is that accurate. Anybody have one to sell? The tripod has 3 silver colored allen head screws sticking out of top of tripod. Looks wrong to me. I removed them. They are sitting on right side of tripod Base. Does the telescope base sit on these bolt heads? This thing is Huge, and Heavy, (what have I done)? I'm used to my 8". It was sold as parts/not working. I was excited to see if it works at all so I hooked up a generic 12vdc adapter and the hand control lit and says Meade, then Telescope. When I plug declination cable in the hand control lights go out and it doesn't respond. Any ideas? Thanks for any input. Jerry

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#2 lambermo

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Posted 11 May 2011 - 03:28 PM

12V will work, it's just slower. I have that when I use a car battery.
The scope does not sit on the bolts, i think the previous owner just stored them there.
Your dec. might have a short somewhere, others can help you further on this

#3 Naturlich

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Posted 11 May 2011 - 05:40 PM

Hey Jerry, welcome to CN forums :)

Lets see:

Voltage: 12v will be fine aslong as you're pusing enough amps (think you need about 2amps), as said it'll just be a little slower, not a bad thing, these are LOUD at full speed.

Spreader: Yes thats typically used to lock the mount to the tripod, and help lock the legs in place for stability. You might get away with it IF the last owner modified the locking screw to the mount so it can tighten up, if not I'd be pretty nervous about using it. (dunno where you can get them though :( )

Allen Bolts: This is probably how the pervious owner locked the mount to the tripod. If you put the mount on the tripod, there are 3 holes that should line up around the edge, put the bolts up through the bottom on the tripod head and bolt into the bottom of the mount to hold it inplace.

If it wasn't bust before, theres a good chance it is now. You should never plug in/remove the Dec cable with the system powered up. Never plug anything in after turning the power on infact. Still with that said, plug it all together and power up, Have a look at the lights on the handsetkeys, they should all light up. Make sure the scope will move in all directions. Do a fake alignment just to make sure it can actually do one, I have a feeling you could be looking at atleast a dead hand controller given he was selling it as repairs. They are hard to get hold of and not cheap, and a very very very common failure on the Classic.

IF you find you have problems with the electroinics/handset, please do get in touch with George Dudas at this link: http://tech.groups.y.../LX200Autostar/ Have a look there and see whats on offer and see if George has any suggestions for you to check the condtion of your scope, he's a great guy and will help all he can, and if it can't be fixed, he has a nice alternative to trying to repair the now very old and dated Classic control system.

Nat

ps keep us posted with how your getting on! :)

#4 Jerry238

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Posted 12 May 2011 - 09:06 AM

thanks Nat, very helpful, Jerry

#5 Skywatchr

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Posted 14 May 2011 - 07:46 AM

Hi Jerry. Yes, use at least 16 volts because with that scope, 12 volts is under powering it and can cause damage. The power supply you used is not big enough. That is why it went "lights out".
Those 3 screws are for attaching the wedge to the tripod. A spreader can be made from plywood if you cannot find one. Just put a wanted ad in the S&S forum. I am sure you will find one.

Jeff

Hi, Just received my new (used) tele and have a couple of very basic questions. It came without a power supply. It says 18 Volt on the electronics box, but from the internet I get that alot of people sell and use 12V adapters with this scope. Is this OK? It is missing the spreader in between the tripod legs. Is seems that this is necessary to actually tighten the the scope to the tripod. Is that accurate. Anybody have one to sell? The tripod has 3 silver colored allen head screws sticking out of top of tripod. Looks wrong to me. I removed them. They are sitting on right side of tripod Base. Does the telescope base sit on these bolt heads? This thing is Huge, and Heavy, (what have I done)? I'm used to my 8". It was sold as parts/not working. I was excited to see if it works at all so I hooked up a generic 12vdc adapter and the hand control lit and says Meade, then Telescope. When I plug declination cable in the hand control lights go out and it doesn't respond. Any ideas? Thanks for any input. Jerry



#6 Naturlich

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Posted 14 May 2011 - 05:22 PM

I doubt very much that 12v is underpowered, since "in the field" it's hard to find a 16-18v supply, most people use a 12v supply or? I'd much more say that the amperage counts. Thats what I always though anyway and seems to make sense.

#7 imjeffp

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Posted 14 May 2011 - 09:09 PM

My Kensington PowerPack has an 18v outlet; it's the only thing I've ever used in the field.

#8 Naturlich

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Posted 14 May 2011 - 09:26 PM

cool Jeff :) Just never heard of the LX200 having issues with 12v, it's not an issue ofcourse for my system, but I thought they were always OK with 12 anyway :confused:

#9 lambermo

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Posted 15 May 2011 - 05:04 AM

cool Jeff :) Just never heard of the LX200 having issues with 12v, it's not an issue ofcourse for my system, but I thought they were always OK with 12 anyway :confused:


I can confirm that at least my LX200-classic is fine in the field with a plain 12V car battery :)

#10 George D

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Posted 17 May 2011 - 09:15 PM

Well, a "12 volt" battery, that's healthy, probably reads a little over 13 volts most of the time. But it could easily dip below ten volts as it drains in use. And not to contradict Skywatchr but I think higher voltages are the bigger problem than a lower one. Most of the circuitry is regulated to five volts on the board and the power that isn't is what goes to the motors themselves. They can certainly handle lower voltages.

Now, it's possible that the old system had loading issues and deficiencies in the power regulation circuits that made it vulnerable to operation faults at lower than 18 volts. If that is the case, it would make sense. Skywatchr knows these scopes and their circuits like the back of his hand, so I hesitate to question his statements about them... But I did :-)

#11 privateeradventu

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Posted 25 May 2011 - 02:25 PM

I am very interested in this also, as i have an lx200 that i got recently and the guy ripped me off for thr 18v converter but i have been using my 12v unit and have wondered if it will be ok or not, so i would sure like to hear more on this one!!

#12 George D

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Posted 25 May 2011 - 03:06 PM

As I see it, there are two potential points of concern, regarding the use of a lower voltage power supply. The first is, do I have enough current to run the electronics at a voltage that is lower than the 18 volt unit supplies, and second, am I going to meet Meades perfomance specs for the unit.

I can certainly imagine that, in order to truthfully publish a slew speed specification for their unit, Meade might have had to up the input power to get the motors to go faster. That might be one reason that some LX200 Classics came with 18VDC input specs.

There may be other possibilities here as well. The on-board circuits appear to be regulated to a five volt level. That means an input voltage of less than say seven volts, may become a problem for the reliable operation of the unit.

Has Meade ever posted any warning about using battery power or operating the telescope at lower voltages than 18 VDC? I don't think so.

Most of the catastrophic failures I have heard about, deal with tantalum capacitors literally burning up and catching on fire. That is often attributed to the fact that the capacitors on most of the Meade circuit boards are rated for a 25 VDC maximum. I have measured voltages from the UNREGULATED Meade 18 VDC supply, as high as 28 VDC! So it's my opinion that it's the higher voltages that present the greatest threat of damage and not the lower ones.

Am I missing something?
"Anyone?...Anyone?.. Bueller?... Bueller?" :lol:

#13 privateeradventu

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Posted 28 May 2011 - 05:41 PM

Thanx this is great! i use the celestron 12v power tank 17 but have not done much yet with it, would prefer a starizona piggyback unit, but want to check things out first!!

#14 Arctic_Eddie

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Posted 29 May 2011 - 09:16 AM

If you really need 18VDC in a portable situation then get a DC/DC switching converter for a laptop. The one for my Acer netbook is rated at 19VDC @ 3.6A. Many others are designed for 18VDC with plenty of current capacity. You will need to check the output plug for the correct size, 5.5mm x 2.5mm x 9mm.

#15 Skywatchr

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Posted 31 May 2011 - 05:09 AM

For the LX200 Classic that is labeled 18v, using a 12v PS will cause it to draw more current during high-speed slews, which in turn causes the PS to overload and drop voltage. That puts a strain on the motors and voltage regulators. It worsens as the temperature drops and the grease thickens. It was a workaround for the design that in the beginning was labeled 12v and a lot of warranty repairs were done. However Meade never changed the tantalum capacitors that began failing to at least 36v instead of the 25v "stock" ones.
Me? I use an AC adapter for the older IBM Thinkpads that put out 16v @ 3.36A or 4.5A depending on the model. They even have the correct plug.

I doubt very much that 12v is underpowered, since "in the field" it's hard to find a 16-18v supply, most people use a 12v supply or? I'd much more say that the amperage counts. Thats what I always though anyway and seems to make sense.



#16 Skywatchr

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Posted 31 May 2011 - 05:14 AM

HA! Unregulated AC adapters will read high when not under load. A healthy 12v battery will have 13.8 volts at no load also, but can drop to around 12.6 on average under load. These classic LX200 scopes are a bit power hungry.

And you are right about the deficiencies of the old circuits. :grin:

Well, a "12 volt" battery, that's healthy, probably reads a little over 13 volts most of the time. But it could easily dip below ten volts as it drains in use. And not to contradict Skywatchr but I think higher voltages are the bigger problem than a lower one. Most of the circuitry is regulated to five volts on the board and the power that isn't is what goes to the motors themselves. They can certainly handle lower voltages.

Now, it's possible that the old system had loading issues and deficiencies in the power regulation circuits that made it vulnerable to operation faults at lower than 18 volts. If that is the case, it would make sense. Skywatchr knows these scopes and their circuits like the back of his hand, so I hesitate to question his statements about them... But I did :-)



#17 Naturlich

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Posted 31 May 2011 - 09:21 AM

Thanks for that! My system is 12v so personaly it's not an issue, but good information, I don't wanna be giving out any bad advice so it's good to cover this :)

#18 George D

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Posted 02 June 2011 - 12:51 AM

HA! Unregulated AC adapters will read high when not under load. A healthy 12v battery will have 13.8 volts at no load also, but can drop to around 12.6 on average under load. These classic LX200 scopes are a bit power hungry.


And you are right about the deficiencies of the old circuits. :grin:

Well, a "12 volt" battery, that's healthy, probably reads a little over 13 volts most of the time. But it could easily dip below ten volts as it drains in use. And not to contradict Skywatchr but I think higher voltages are the bigger problem than a lower one. Most of the circuitry is regulated to five volts on the board and the power that isn't is what goes to the motors themselves. They can certainly handle lower voltages.

Now, it's possible that the old system had loading issues and deficiencies in the power regulation circuits that made it vulnerable to operation faults at lower than 18 volts. If that is the case, it would make sense. Skywatchr knows these scopes and their circuits like the back of his hand, so I hesitate to question his statements about them... But I did :-)


Now WHO can argue with THAT? I'd like to thank Gabby Johnson.... Er; I mean Skywatchr for clearly stating his observations about this product. :grin:

Well; I could probably argue a little but I think this time I'll just say.... RUGGER! :roflmao:

#19 Hamsterdam

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Posted 19 June 2011 - 10:02 AM

Gabby Johnson is right. Not only was that authentic frontier gibberish, but 12v batteries dont stay at 12 all night. I bought a powertank for my LX200. It has 2 12v cigarette outlets and 2 120v outlets. The screen reads 13.8 most of the time, better at others. I am in agreement with amps being the killer. Mine has the bonus of also being a jumpstarter, so I can charge it via the car battery, should it weaken....but first time out, it never moved a bar off of full power in 6+ hours, but never mind that *BLEEP*, here comes Mongo!

#20 budman1961

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Posted 19 June 2011 - 10:12 AM

Got to love that movie...Howard Johnsons had only 1 flavor, and Harvey Korman......what a classic! Brook's quote "Always remember affairs of state, will always take precedence over affairs of state" How appropriate today!

#21 Bill_Marq

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Posted 19 June 2011 - 11:26 AM

You guys have me wondering. I bought my 10* LX200 in 1993 or 1994. The DC input jack is labeled "12VDC" and it came supplied with a 15VDC power adapter with a car battery connector option. It still works fine after all these years. When on a battery, there is a noticeable slow down in speed when the battery voltage drops after several hours of use. That's when I shut it down.

Just how many power variations were there?

#22 George D

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Posted 19 June 2011 - 02:20 PM

OK; I guess I can't resist adding another two cents worth here.

The current needed to run these telescopes is miniscule compared to a sealed lead acid battery of any size. We're talking less than an amp most of the time with occasional spikes to two amps maybe. But even the power hog that is the Classic control will only measure one amp on it's panel meter. So, of course, the battery will stay at nearly a fully charged state most of the night, if it's a healthy battery and has any size at all.
Do more amps kill the circuits? Why would they? The circuit limits voltage and current I believe and there is no reason for the lack of voltage to cause more "strain" on the system.
What could happen though is a controller anomally, like the processor "getting lost" due to a low voltage condition and causing things to happen that shouldn't; Like a rapid dithering back and forth in direction on one or more motor axis causing essentially a "short" in the system, blowing the fuse and perhaps damaging a driver chip. But to get there, the five volt regulator would need to see less than maybe seven volts momentarily. That could happen as a battery that is already weak drains to a level in that range and a surge in current as a high speed slew begins.
Otherwise, you'll get no "harumph" from me governor. :grin:

I have a Black and Decker power unit myself. But I have actually run my LX200 using the Autostar Kit on a battery pack included with many of the ETX scopes for over an hour before. We're talking ten AA Alkaline batteries here. RUGGER! :roflmao:

#23 Hamsterdam

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Posted 29 June 2011 - 03:53 AM

I didn't get a Harrrumphh! from him.


That's why I had to add that. It was either that or "Today we will be reading from the books of Matthew, Mark, Luke, and.....DUCK!

#24 Hamsterdam

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Posted 29 June 2011 - 04:12 AM

My thinking on Amperes, is that just as they are the part of electricity that kills people, and that if he had a more than nominal spike, say 5-8 amps, it could...just could...blow right through the regulator. When I need to find a charging brick for something in the house, I am much more concerned with amps, sometimes milliamps than the volts, which are also important, but I still place more stake in what amps can do. With a Van de Graf, you can run thousands of volts through your body, and only raise your hair, add an amp or 2...bye bye.

I know you know that, but I wanted to point out how Amperes can cause problems...huge problems if you run too many of them through your body. My 32,449,01 Pesos...probably still not worth 2 cents :)

Im thinking larger scale here, but we once got a direct lightning strike to our transformer. My comp was plugged into an Isobar, plugged into an APS UPS system, then the wall and it came right thru all of it, as if there wasn't a breaker box or anything. Our land line phone actually looked like it had a small ball lightning coming from the receiver for about 4-8 seconds...seemed like forever, just not a long enough forever to get my camera ready.

As you know from my posts, I try to eliminate the ridiculous as well as the sensible. I doubt a car battery could spike it that much, but wait....Id disconnect on startup...just as precaution...I still doubt, unless you have a car with a bad regulator, you should be ok....and dagnab it, consarn it, I missed getting my Harrumphh in in time.

#25 macona

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Posted 26 July 2011 - 01:30 PM

Running the scope on less voltage will not cause it to draw more current. It just wont go as fast. For a motor, current is torque and voltage is velocity. The only concern with running at a lower voltage is that the logic circuity gets enough voltage for its regulators. 12v is fine for the 7805 which is used for the +5v source.

I use a 12v laptop adapter with mine as well. 12v in 18v out.

A battery will not spike, ever. Thats why you can get away with very simple drive circuits for laser diodes which will fry in microseconds in an overvoltage condition. Batteries are the most stable power source known.

Did you get you dec running? If not two possible problems, one is the current rating is not high enough on the power pack. Second is the encoder board on the Dec axis has a tantalum cap that could be shorted or partially shorted.






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