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Replacement Power Transformer Wiring

I ordered a replacement power transformer for a pair of AV-40 monitors. The original transformer has two wires on the primary side of the transformer. That makes things easy.
The replacement transformer has *5* wires on primary side of the transformer. Please see attached picture.
For 120V US operation, which set of wires should be connected to 120V?
Thank you,
-Shawn
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  • Hi Shawn,

    Thanks for posting.

    This is something you'll want to contact an authorized service center or distributor about. I'm not sure they'll be able to assist with self-servicing a product, though.

    Contact the support team or the distributor in your area for some more info. Thanks!

    USA & Canada
    Phone: 401-658-5765
    Hours: Monday - Friday 8:30AM - 6:30PM EST

    Germany
    Phone: +49-2154-81299-20
    Hours: Monday - Friday 9:00AM - 5:00PM CET

    UK/Europe
    Phone: 44(0)1252-896040
    Hours: Monday - Friday 9:00AM - 6:00PM BST

    Brazil
    Phone: +5511 - 3222-6476
    Hours: Monday - Friday 9:00AM - 6:00PM BRT

    Email
    http://www.m-audio.com/support/contact
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  • Hey Shawn! Where did you purchase this transformer from? I have been looking and can't find one with the right voltage.
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    Hello Branden.
    It has been a while since I repaired that unit for a friend. If I remember correctly, I ordered it from the company. The one they sent was not an exact replacement. It was close, but not exact.
    The transformer's primary winding was made to be connected to a selector switch so the user could select 220V input or 120V input. I was very fortunate to access to test equipment so I could figure out the wiring to wire it for 120V operation in the US.
    Sorry. I don't have any notes on which wires were connected to which windings. With the right test equipment, you do it right, it works. Without the test equipment, you do it wrong, it's a short to AC and you pop a circuit breaker - if your lucky. If you're unlucky, things catch on fire.
    More specifically, at that time, I had access to a current limiting, variable, Elgar AC power source. I set it to something like 10 VAC on the primary side and looked for something like 2 VAC on the secondary. The trick is finding which two wires you tie together, and which two you apply the input voltage to. Do it right, it works. Do it wrong, things burn up.
    Good luck. :)
    -Shawn
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    Oh, I just wanted to add something. Because I couldn't guarantee that the company would send the exact same transformer, with the exact same wiring, in the exact color scheme, I did not post my results here.
    If I did, it would be possible that the vendor could use a different color of wire, and someone would wire it incorrectly, and then the transformer could cause damage or a fire.
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  • Totally understood and thanks a ton for the answer, especially a year later!
    Thanks, Shawn!
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