Welcome to the SeeMeCNC Community

I just finished building the Rostock Max V.2. I'm in the process of calibrating it and I am verifying extruder stepper operation following the matter control 1.2 instruction in the manual.
I have hea\ted the extruder to 190 (per the instructions} but when I push the E+ button, nothing happens. I have tried reversing the wires and plug in the RAMBo board and no change. All the connections appear to be good.
Any suggestions would be great.

I'm new to this myself, but I would double check that the extruder is plugged into the correct port on the Rambo. Also, if you have a multimeter, put it on continuity mode and make sure the wires are not broken or shorting.

The first thing I'd check, though, is to make sure the Rostock is connected (I assume you're using matter control) and the computer hasn't gone to sleep. My limited experience is that going to sleep, then waking it up and trying to do things confuses the Rambo, but that might just be me.

I am also having this problem. Its seems to be the only place in the manual that doesn't give any suggestion of what to do in this case. Did you find the solution??

Thanks.