Hello, I have been attempting to calibrate my extruder but unsuccessful. I am new to 3d printing. I have a prusa with printrboard revd electronics. It comes preloaded with marlin and I have found online that calibration happens through marlin. I have downloaded arduino, teensyduino, and marlin and attempted to change the values then load onto printrboard. The marlin file seems to have some problem with it when i try to verify. Am I on the right track or far off? Any help would be appreciated.
Thanks!

It's possible to change these values through the mechanism you are using, but it's probably easier to just do it through g-code. Through pronterface, or whatever host software you are using, you can change the E steps value on the fly with the 'M92 Ennn' command (you can do the same thing with the other axes) and then after you determine the best value, you can commit to it.

If you have marlin configured for EEPROM, then you can commit to the new value(s) by entering gcode 'G500'.

If you do not have marlin configured for EEPROM, then you need to go your route and change the source code, rebuild and upload.

Yeah I would rather do it through pronterface which seems easier. This may seem basic, but how do you change the e step values through pronterface with the M commands? and also how would I save these settings after I change them? Not sure if my marlin software is configured for that. Still has the original marlin loaded on it from printrboard. Thanks for your help I appreciate it!

pronterface has an entry field (on the lower right I think) where you can enter Gcode commands directly and send them to the printer. M92 Exxx sets your extruder Esteps value to xxx.

Out of the box, Marlin has EEPROM disabled (at least it did when I started with it). You need to make changes through the arduino IDE in order to turn it on. I think you'd have to assume it's not enabled, so the only way to commit your changes is to modify the source code in the arduino IDE, build and upload the firmware. It's a good thing to know how to do anyway.

My earlier point though was that while you're experimenting with different values, it's much easier to use the M92 command.