R2 replacement board by Partsbuilt.com

I have been testing this 2nd revision. it has some neat features. It has a 24v connector for using a 24v system fan, it has Z2 endstop for those that would use the board in a dual Z stepper system. It has resistor footprints in parallel with the 4.7k Marlin pullups. This allows for higher precision resistors or modifying the slope of the hotend thermistor for better resolution. Since it uses 4988 stepper drivers ( but you can use any compatible driver boards ) the current reference can be adjusted from the existing 0.9v to 1.2v allowing for faster higher current steppers.

There are separate reset-able fuses for 5v and 12v. There is an extra 5v and 12v connector.

The board does not require any rewiring and you can unplug the existing board and plug this one in.

I found the hotend temp regulation to be +/- 0.3C.

And last but not least is that all of the boards are common easily replaceable parts.

Shown is my install. I use the larger 17hs8401 steppers for faster motion and higher torque. I set the reference voltage to 1.2v rather than the 0.9v used on xxx02 steppers like the ones Robo supplies. The install is pretty clean. I noticed that Robo left the metal sheathing on the hotend cable past the plastic armor sheathing. Robo runs this under their board and it could be the source of failures, by shorting out the boards. I cut off the metallic sheathing before running under the board. The two higher current connectors for the bed and hotend heaters are pushed up the well on the right so as not to short anything.

I use the cheapie 3950 on the hotend and the hotend and the bed agree with each other and my thermostat and have a spread of 1.5C at room temp. The resistors on this Ramps board are 1%.

The power supplies are overkill and will allow you to run your fans at 100% all day long without damage.