Review on SainSmart Genmitsu 3018 PROVer Machine Controller by Tommy Rao

The components used on this board are great, it has Toshiba 4A tb67s109afng stepper drivers with thermal protection under that little blue heatsink. The motor driver has a good common mode choke and has no problem supplying enough 12V power to the laser. The problems arise due to the actual design of the board. The stepper current control isn't really routed properly and only has a potentiometer adjusting from Vref to ground instead of a voltage to ground. The end result is that the maximum Vref setting at these currents is about 0.2V or 0.18A step current. Motors easily lose steps when you're actually cutting something and have almost no power. The solution is to put a 10k resistor on the 24v rail from the test point for vref. This makes the maximum adjustable step current setting about 2.2V or 2A. I suspect that this very low step current setting is intentional, since the heatsink is bonded to the drivers with silicone instead of thermal paste, rendering the heatsink nearly unusable. even with thermal paste it's not quite adequate and it really should have a fan like all cheap 3018 drivers. . but what's the point if I have to do all the work myself.