I am using the M1-ATX to power my Fit-PC2, which operates on 12v and also my Lilliput 629GL.
Because it doesn't have an ATX connector like a regular MOBO, I jumped the green/black wires to get the power supply enabled and then used a Yellow wire to supply my 12v source.

The M1 should handle an input voltage of 6-24vdc and when I am cranking, it only drops to about 9.5v so I am well within the limits, however, when I am cranking, I lose the 12v and my Lilliput and PC both shut off immediately.

Yes, I have the correct wires on the J11-J13 jumpers for power, ignition, ground.