The power jack should have a little diagram that shows the ring and tip. The ring is the long sleeve on the plug, and the center would be the tip. The diagram should show the polarity. It's usually minus to the outer sleeve (ring), and plus to the tip. It might be on the adapter spec plate also. How to tell polarity expected of DC barrel jack The circuit board should indicate the polarity (plus and ground).
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The power jack should have a little diagram that shows the ring and tip. The ring is the long sleeve on the plug, and the center would be the tip. The diagram should show the polarity. It's usually minus to the outer sleeve (ring), and plus to the tip. It might be on the adapter spec plate also. How to tell polarity expected of DC barrel jack
The circuit board should indicate the polarity (plus and ground).