7 replies to this topic

[Nederbasse]

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

[MistrBadgr]

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

[RickScofield]

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.

[Meade]

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. 

[Mark Sibole]

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

[RickScofield]

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

[doctorstork]

What is the polarity?

[MistrBadgr]

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