Extruder Controller v3.7 Dual Head

I wanted to buy an Extruder Controller from Makerbot but they are out of stock. And have told me that they are not likely to get any back into stock soon. So I decide I will make one and find out that three of the components on the board are no longer manufactured! So I decided to redesign the makerbot's extruder board and here is a drop in replacement.

It's been designed to be dual steptrude compatible as I have removed the DC motor controller (As the have stop making that chip and upgraded it to a small package version).
It has upgraded Mosfets (again they stopped making the one on the MECV3.6) and have added two more in place of the dc motor controller. And Maxim-ic are stopping production of their thermocouple chip, so that also has been updated.

I've added a ATXV12 connector that drives the Mosfets. Currently the connector is rated at 300watts which should allow for more power to be delivered.

I've also include the option to either use the on board voltage regulator or 5