Jump to content


Photo

Power supply


  • Please log in to reply
7 replies to this topic

#1 Nederbasse

Nederbasse

    Newbie

  • Members
  • Pip
  • 9 posts
  • LocationVodskov Denmark

Posted 14 October 2014 - 07:26 AM

Hi

I have a 9 volt power supply that has a Max: 18W and Max: 2A warning 
Can it be used for my EXT 90 PO
 
Lars 
Denmark


#2 MistrBadgr

MistrBadgr

    Advanced Member

  • Administrators
  • 2955 posts
  • LocationBroken Arrow, Oklahoma

Posted 14 October 2014 - 12:59 PM

Hi Lars,

 

Someone that owns an ETX 90 should probably verify this, but I believe your power supply should work just fine.  It can support enought amps.  I believe the scope can handle 9 to 12 volts with no problems.  The big issue is making sure the polarity is correct.  Getting that wrong has an awflully bad habit of  frying the electronics.

 

Bill Steen


Bill Steen, Sky Hunters' Haven Observatory, Broken Arrow, Oklahoma

#3 RickScofield

RickScofield

    Advanced Member

  • Members
  • PipPipPip
  • 323 posts
  • LocationBellevue,Nebraska

Posted 14 October 2014 - 06:27 PM

Lars,
I have an ETX 90 MAK and the power requirements are 12V DC, 1000mA at least that is the power output specs for Meade 546 AC adapter used for it, the ETX 80 and the ETX 70. I agree with Bill regarding 12 or 9 volt as long as it does not exceede 12 volts.

#4 Meade

Meade

    Meade Instruments

  • Administrators
  • 178 posts

Posted 16 October 2014 - 07:44 AM

The only danger is reversed polarity which would blow the electronics. As in instantly. 

 

The low voltage would not permanently hurt anything but low voltage can cause odd effects, possibly intermittent, like motor faults, random resets, and so on. If you try the unit and get such effects switching back to 12V via battery source or the Meade 12V power supply should clear it up. 

 

Best Regards, 

 

John Piper

Customer Service Manager

Meade Instruments Corp. 



#5 Mark Sibole

Mark Sibole

    Advanced Member

  • Administrators
  • 2368 posts

Posted 16 October 2014 - 12:49 PM

Just catching up here.John is correct.You MUST make sure you follow proper polarity of the electronics will fry instantly!A lower voltage will not hurt anything BUT it can cause problems.It may work fine but generally low voltage does not supply enough power to specific voltage needs of chips and regulators.Its like running the scope on batterys and working fine at 12 volts but as voltage drops you start to get errors of different things.At what point theses errors will occure can vary.Even a .2 volt drop can be the difference between working fine and not working at all.You can try it as it wont hurt so long as you have the correct polarity.You may get lucky and it will work fine but no guarantee. But I personally would add an inline fuse to any external power supply.Its an insurance policy IMO.

I hope this info helps

Regards

 

mark


Mark Sibole
MTSO Observatory
Fife Lake, Mi.

http://astronomy.qteaser.com

#6 RickScofield

RickScofield

    Advanced Member

  • Members
  • PipPipPip
  • 323 posts
  • LocationBellevue,Nebraska

Posted 19 October 2014 - 03:10 PM

Lars,
I would probably NOT use the 9 volt power supply for your ETX 90 , these are 12 volt devices with 12 Volt DC motors and power distribution componets. You may get the same performance as one gets with weak batteries. I myself believe this to be hard on hardware.
RickScofield

#7 doctorstork

doctorstork

    Newbie

  • Members
  • Pip
  • 2 posts

Posted 19 January 2016 - 01:02 PM

What is the polarity?



#8 MistrBadgr

MistrBadgr

    Advanced Member

  • Administrators
  • 2955 posts
  • LocationBroken Arrow, Oklahoma

Posted 19 January 2016 - 02:21 PM

If it has an attachment for the battery holder like what snaps onto a 9 volt battery, the polarity will be the same as if you plugged a nine volt battery onto it.

 

Bill Steen


Bill Steen, Sky Hunters' Haven Observatory, Broken Arrow, Oklahoma




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users