Model with double hight [SOLVED]

[Napalm]

Hi,
I bought a Acrylic Prusa I3 Pro B set a few days ago and assembled it.

Yesterday I did my fist print and I was very impressed. Looks really good.

I did not update firmware or changed any settings. Its all out of the box

When I print a testcube with 20x20x2mm the result is 20x20mm but about 4mm high.

I tried a few other models, but it seems, that all models are about double in hight.

How can this be? How can I correct this?

regards
Mirko

[William]

How could this be...
Did you add a raft to your printing object??
And have you measured if the Z axis moves correctly before you print?

[Napalm]

Hi all,
it took the moderator a few days to approve my message, so meanwhile I found the solution.

Ok, in case anybody has the same problem, here is the reason and the solution.

On the GT2560, under the motor driver for the z-axis there are 3 jumpers. They are all set/closed by default which is a 1/16 step.

One of the jumers, the 3. one, was set, but broken. It did not work properly, so it did not make contact. I exchanged the jumper and everything is OK, now.

It is because not setting the jumper (or having a broken jumper) makes the motor driver think it is a 1/8 step motor, but the software thinks it is a 1/16 step motor and gives twice as much commands to turn the engine. So the object is twice as high

Simple broken jumper caused the BIG problem

Hope this helps others
regards
Mirko

[Napalm]

* posted same text twice *

[William]

Hi,Mirko
Thanks for your sharing.