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Finding powe supply polarity from the circuit board?

drbob

Jan 25, 2013
2
Joined
Jan 25, 2013
Messages
2
Hello,

I've been asked to order a new power supply for a device that unfortunately does not indicate the polarity of its 12V DC barrel jack. I would greatly appreciate it if someone here could help me work out the correct polarity (centre pin +ve or -ve)

I've attached a photo of the circuit board. It looks like a trace runs from the centre pin through a fuse and up to a choke coil, my very limited knowledge of electronics suggests to me that this means positive charge probably flows from the centre pin, is this correct?

kind regards,

drbob
 

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GreenGiant

Feb 9, 2012
842
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Feb 9, 2012
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842
that looks like it would be center positive, if you notice the ground plane at the top of the picture runs to the side of the plug housing.

I can't say with 100% certainty, but the fact that there is a fuse right out of the center pin and what looks like a ground plane is attached to the side connection of the DC input pin is a pretty good indicator.

Do you now have the original plug for this device?
 

drbob

Jan 25, 2013
2
Joined
Jan 25, 2013
Messages
2
Unfortunately the original power adapter has been lost. I tried sending an e-mail to the manufacturer but they didn't get back to me.

Thanks for your input, I think I'll try with a centre positive power adapter.
 

Rleo6965

Jan 22, 2012
585
Joined
Jan 22, 2012
Messages
585
I agree with GreenGiant. Its centre +VE. Negative side of Capacitor was soldered on etch of PCB. Follow the trace and this lead you to negative of Plug. See photo.

REMOTE.jpg
 
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