Universal M400 decoder power supply help

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Torquetube

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Jun 4, 2012
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Hi all,

I have found an old Universal Radio M400 decoder in a box but there is no power supply for it, from what I've read it's 12volt but I can't find if it's positive or negative centre? Anyone know??
 

chaycock

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I cannot give you a definitive answer, however, generally, the center is positive and the outer ring is negative. You may also try contacting Universal directly, they are still in business.
 

Torquetube

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I was thinking along the same lines as well but didn't want to risk damaging the unit. I've tried emailing Universal a while back but I never got a reply :-(.
 

LesWurk

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it's center + marked on the supplied wall wart , manual calls for 11-16 volts @ 200ma, wall wart Universal supplied says 400ma
 

ka3jjz

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it's center + marked on the supplied wall wart , manual calls for 11-16 volts @ 200ma, wall wart Universal supplied says 400ma
which is totally safe. In fact the Universal wall wart might last a tad longer because it's going to run cooler.

Mike
 

N9JIG

Sheriff
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If you have an ohm meter you can verify that it is center positive. If the ring side of the jack shorts to the case and the tip doesn't then the center is positive.

The majority of consumer electronics uses center positive but there are just enough oddballs out there to make it challenging sometimes...
 
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