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Bill_Marq
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Reged: 06/07/11

Loc: California and Arizona
Re: Newbie question about Meade Classic LX-200 new [Re: budman1961]
      #4647401 - 06/19/11 12:26 PM

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?


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George D
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Reged: 04/13/10

Loc: So Cal
Re: Newbie question about Meade Classic LX-200 new [Re: Hamsterdam]
      #4647652 - 06/19/11 03:20 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.

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!


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Hamsterdam
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Reged: 03/23/11

Loc: smack dab in the middle of the...
Re: Newbie question about Meade Classic LX-200 new [Re: budman1961]
      #4664338 - 06/29/11 04:53 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!


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Hamsterdam
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Reged: 03/23/11

Loc: smack dab in the middle of the...
Re: Newbie question about Meade Classic LX-200 new [Re: George D]
      #4664345 - 06/29/11 05:12 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.


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macona
sage
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Reged: 05/18/11

Loc: Beaverton, OR
Re: Newbie question about Meade Classic LX-200 new [Re: Hamsterdam]
      #4713976 - 07/26/11 02:30 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.

Edited by macona (07/26/11 02:32 PM)


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Hamsterdam
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Reged: 03/23/11

Loc: smack dab in the middle of the...
Re: Newbie question about Meade Classic LX-200 [Re: budman1961]
      #5809432 - 04/19/13 07:53 PM

That's HEADLEY Lamar!

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cavefrog
Carpal Tunnel
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Reged: 11/11/08

Loc: loozyanna
Re: Newbie question about Meade Classic LX-200 new [Re: Hamsterdam]
      #5812160 - 04/21/13 12:39 AM

as far as I understand, if one has a 15v power supply that is putting out 15v with no load will drop to about 12 volts when loaded. depending on how much load is placed on the power supply will determine how much of a voltage drop.

do we remember Ohm's law? I_R_V

Theo


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