Question about Line 6 JM4 Looper

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Power supply polarity

My power supply for my line 6 JM4 Looper was dead on arrival. Does anyone know what polarity it is. does it need to have a 2000 ma power supply to work?

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Most of the time these things will have the negative in the middle of the socket and positive on the outside. I have found this true on most musical equipment but, other electronics will usually have the opposite. If it says 2000 mA, it has to have at least that much current to work properly, more is ok, less is not. Voltage must be the same to avoid damage. FIRST, I would definitely check the power supply with a test meter to be sure it is dead. The socket has a switch mechanism to turn on the battery when it is unplugged which could be stuck. If it were mine, I would take it back where I bought it and let them deal with it.

Posted on Mar 29, 2014


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I suspect the input voltage from the supply is way lower than the required.

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Well, you might try:

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