Marlin dual extruder set-up instrucrions?

I've set-up a dual extruder machine and am trying to get Marlin configured corectly.

Currently I've managed to set it up to recognise it had dual extruders.

Each extruder can be selected in Pronterface and heats-up correctly.

However, when I press the extrude button, the first extruder runs fast and rough.
The second runs smooth and at normal speed.

I haven't been able to find a compleate set of instructions for dual extruders under Marlin.

I've found posts with partial information, that has gotten me this far.

Also in those posts, I've seen reference to setting the extruder offset in the firware rather than the slicer, but coulden't find how.

I beleave I'm using the latest release for Marlin.

Any help, questions or pointers to compleate docs welcome.

Thanks,

In Marlin, steps/mm, max speed, and acceleration for each extruder are the same. In other words, Marlin assumes both extruders are identical. So, commanding E0 to move at some speed and distance should have the same result as commanding E1 to move that same speed and distance. Is the Vref on each extruder stepper driver set the same?

Also, a quick text search for "offset" in Marlin's Configuration.h reveals where you can set the extruder offsets:

// Offset of the extruders (uncomment if using more than one and relying on firmware to position when changing).
// The offset has to be X=0, Y=0 for the extruder 0 hotend (default extruder).
// For the other hotends it is their distance from the extruder 0 hotend.
// #define EXTRUDER_OFFSET_X {0.0, 20.00} // (in mm) for each extruder, offset of the hotend on the X axis
// #define EXTRUDER_OFFSET_Y {0.0, 5.00}  // (in mm) for each extruder, offset of the hotend on the Y axis

I'm sure I set the pot on each polulu the same, but I'll double check.

Can't find those lines in either Configuration.h or Configuration_Adv.h

Will double check for newer Marlin...

Polulus are set the same.

Marlin version is the latest. Marlin_v1.zip

swapped the polulus, same result.

The latest Marlin does contain those lines. Where are you downloading from? You should be downloading it from the main GitHub repository here: [github.com]

So you've ruled out the possibility that it's the Pololu causing problems, that's good. Next you should swap the extruder steppers' plugs and see if the problem switches motors.

As a last option you can download the newest Marlin from the link above, input your configuration, re-upload to the Arduino, and see if the problem persists.

I have swapped the motors, and the behaviour goes to the new motor.

I did get my Marlin from github.

...

Doh!

I had the old version arround for an older printer and mistakenly used that.

I'm looking at the right one now. Gotta move the changes across...

Hopefully that will fix my problem.

Let you know when it's tested.

O.K.

I was using an older Marlin on the printer. I did have the newer version, but when I was looking for those lines, I compleatly missed them the first few times.

Having ruled out the motors, wireing and firmware, I decided to look at the jumpers on the RAMPS board.

This was an unusual board for me as all the native jumpers were colourful. Red, Yellow and Blue, rather than the regular Black. I had used the Black ones to fill the pins under the second extruder driver board.

I pulled these colourful jumpers and one actually lost its top while prying them out. After re-seating them, the motor ran more smoothly. It was still rougher than regular, and faster, but better.

So, I pulled out all those coloured jumpers and replaced them with a set of Black.

Now the motor behaves as expected!

Thanks for all the asistance! It helped me narrow down and locate the actual problem.