G0704 Motor Spindle Control

Busted out the multi-meter and started poking around the inner workings of the G0704 DC motor drive.  

I was able to identify three pins called P1, P2 and P3 that can be tapped to control spindle speed from Mach3 using the MX3660 breakout board.

Basically I need to pull power from pin P3, ground P1 and reference P2.  The reference voltage supplied at P2 from the variable range output 0 to 10volts (or max supplied voltage) of the MX3660 is what controls the speed of the spindle.  The monster is alive! 

To control this spindle to be on or off I need to use a relay.  Since the MX3660 has 4 outputs each supplying 24volts at a max of 70ma of power I decided to order this already assembled relay board.  Free trial of amazon prime? Yes please.  Three dollar next day shipping? Yes please.

http://www.amazon.com/gp/product/B00IRU0NUC/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

more to come later dudes