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Little help for Akai PM-750 repair (voltage selector)

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winsdamien picture

Hi all,

I need a little help to repair my Akai PM-750 amplifier (part of system mx-750).

The voltage selector has broken and I don't know wich wires shoud I put together to get it work under 240V.

Service manual is no help, they just give spares parts...

Huge thanks to who could help me :-)

imrus101 picture

You can find the connection of the voltage selector and the mains transformer on page 154 of the service manual - see SzBalint's link. Based on this, you should connect the yellow and orange wires to get the two 120V primary windings connected in series.
I would recommend to remove all wires from the voltage selector switch. Make a quick check: measure resistance between any two of the blue, white and orange wires; you should get the highest reading between the blue and orange. Repeat with the yellow, brown and red wires, you should get the highest value between the red and yellow. This value should be very close to the one you measured between the orange and blue.
Now you can connect the yellow and orange wires, leave all the others unconnected. Isolate all the wire ends properly.


bolykys picture

Hi winsdamien!
The solution is in the service manual linked by SzBálint.
In the service manual, the yellow wire on the voltage selector is blue in your device.
Before you connect the wires, measure it to make sure that these are the coil ends with the highest resistance.



SzBálint picture


winsdamien picture

Thanks a lot  smiley