We have supervised the manufacturing of this MK2B heat beds.

3D Printing
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1

We have supervised the manufacturing of this MK2B heat beds. They are totally flat, the copper is not plated, and the color is really wonderful. If you want to distribute those on your website, please, contact us!!
http://www.printallthethings.com/heat-bed/45-heatbed-mk2b.html

2

If you use a 12V (most common) You must connect BOTH the 2 and 3 pads to the negative, and the 1 to the positive.

3

no, D9 is usually for the fan, you can use the same cable for the connection