Yupiteru MVT-7100 - DC 12V socket -polarity?

[NickBT]

I have just acquired an old MVT-7100 scanner. I'd like to power it from an external supply. I would be grateful if a forum member could tell me (from their personal experience) whether the inner or the outer of the connector is +ve? I would hate to damage the scanner. All informed replies will be gratefully received.

 

[cmjonesinc]

If you trust this picture, it's center positive.

 

[prcguy]

You can also ohm out the center and ring and see which is common to the ground side of the BNC.

 

[bagmouse7]

The center pin is positive.
From page 5 of the user manual:
12 Volt External Power Jack The centre pin is positive. Used to connect the mains power charging unit or DC cigar lighter lead to the MVT-7100.

https://octopup.org/img/stuff/manuals/Yupiteru-MVT-7100--Wide-Band-Hand-Held-Receiver--Scanner-Radio--Operating-Instructions.pdf