caheaton
super member
Reged: 05/26/09
Posts: 157
Loc: SW Ohio
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Hello, can someone tell me what is the voltage output of the Meade #546 AC adapter that is sold for use with the Meade ETX line of refractors? (60,70 and 80). The scope uses 6 AA batteries (9 volts), but looking closely at the photos of the adapter it looks like it puts out 12 volts. If this is indeed the case, I can bypass the adapter altogether and make a cable to connect this to jumpstarter I have. Thank you!
Craig
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oldsalt
Astro Philosopher
Reged: 02/12/05
Posts: 8671
Loc: Pa - between starparties
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The jump start should work just fine. I've used a Husky jumpstart on my ETX70 with no issues.
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There are no winners in war, only bigger losers.
Jim
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cnstarz
professor emeritus
Reged: 12/22/07
Posts: 549
Loc: Kentucky, USA
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Make sure you have the polarity correct. I've seen a few threads warning about frying the control circuit.
Cheers,
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Matt
Apogee 50mm BB scope
ETX-60 BB
Meade 70-az
5" DIY Newt (wip)
C6-N on CG-4 GEM
Gallery
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oldsalt
Astro Philosopher
Reged: 02/12/05
Posts: 8671
Loc: Pa - between starparties
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You can get a pre-made cable from Astronomics, or Scopestuff and avoid the whole is the polarity right issue .
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There are no winners in war, only bigger losers.
Jim
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caheaton
super member
Reged: 05/26/09
Posts: 157
Loc: SW Ohio
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Polarity isn't a problem, I'm used to finding my way around electronics and electricity...I initially was afraid I'd either have include a voltage regulator or get lazy and buy the adapter. Thanks for all the info!
Craig
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oldsalt
Astro Philosopher
Reged: 02/12/05
Posts: 8671
Loc: Pa - between starparties
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No problem Craig. The only issue you'd have with a jumpstart powering the n mount is if there was a short. As we both know that would not do wonders for the electronics.
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There are no winners in war, only bigger losers.
Jim
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caheaton
super member
Reged: 05/26/09
Posts: 157
Loc: SW Ohio
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It does make me wonder, though. Why did Meade design th ETX refractor line to use a 6 battery pack (9 volts) while the CAT line uses an 8 battery pack (12 volts)? It appears that they are using the same 12 volt motors? Perhaps they were looking to reduce weight? (although not much would be saved, maybe a pound when all was said and done) Strange....
Craig
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oldsalt
Astro Philosopher
Reged: 02/12/05
Posts: 8671
Loc: Pa - between starparties
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The real draw is the amount of current.
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There are no winners in war, only bigger losers.
Jim
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astrowolf67
member
Reged: 12/15/07
Posts: 94
Loc: Western Kentucky
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My ETX 60's, and 80 run fantastic off of a 12 volt jump pack. It costs less than 10 bucks to make an adapter, and, the only worry is polarity.
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David
"Seek the Spirit of the Wolf, for He holds the Secret of Life."
Edmund Astroscan/Meade DS 2000 tripod
Meade ETX 60
Tasco 60mm EQ
Meade 114 NT/LXD75
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Treehopper
professor emeritus
Reged: 07/29/08
Posts: 582
Loc: Upstate NY
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The voltage tolerances of the smaller ETX's is pretty astounding, actually. They're made to run passably well on as little as around 7 volts, maybe a skosh less even before you start getting into "Motor Failure Error" territory. And it will just as readily take a 12 volt supply (in some cases, the field supplies with no other load actually output a bit more than 12 volts.) Whichever engineer planned for that sort of variance in juice deserves a raise. 
I've got all the materials here to make my own DC adapter, I even have an old cell phone car charge unit I'm planning on cannibalizing. Just need to get the 9v cell clip and solder it all up. Shouldn't be a problem keeping the polarity straight, so far as I can tell they didn't do anything weird like flip the leads on the 9v mate inside the mount. So we should be good to go.
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Tim
Champion of small aperture scopes everywhere!
Meade ETX-125PE
Meade ETX-80
Celestron FirstScope 76mm Mini-dob
 Updated: 09/16/2009
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