Prusa i3 build with homing issues

Hi All,
I have built a Prusi3 from scratch. I've gotten my firmware (Marlin) loaded and have been able to home Y and Z axis. I am having trouble with my X. When I jog from Pronterface the extruder travels in the expected direction. If I flag the mechanical endstop i can see that it registers as X min endstop when I issue a m119 command. When the x-axis homes, it will hit the endstop but try to continue (teeth jumping on pulley)
If I invert the x-direction: #define INVERT_X_DIR true, then the axis will home against the mechanical enstop just like it does on the other axis. But the problem is that when I jog X+ the axis travels in the -dir.
So then I flip the motor connection so that it is traveling as expected when i jog. But when the axis homes, it goes in the wrong direction. So I change: #define X_HOME_DIR from (-1) to (1). This will supposedly head it in the MAX direction but I have already inverted travel so it sends the axis to the mechancal stop MIN. But when it hits the stop it wants to keep going.

I feel like I'm missing something basic.
Thanks in advance for any help.

In pronterface if you press X + the carriage should go to the right.

If the X endstop is on the right side it is a MAX endstop and you need to use the MAX jumper position on your RAMPS.
If it's on the left then it's a MIN endstop and you use the MIN jumper position on the RAMPS.
You also need to change Marlin #define X_HOME_DIR -1 for MIN and #define X_HOME_DIR 1 for MAX

Steve

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My updated Instructable on our Prusa i3 Build
[www.instructables.com]

Steve,
Thanks for your responce. Makes perfect sence. I implemented and am on my way.
BTW: snooped around your other posts (great list of tips). I'm a fan of instructables but didn't concider it as a resource. Wonder why it never comes up on google search when troubleshooting.
Thanks again and happy new year
Peter

Hi Pedro,

May I ask what configuration you have.

I am trying to find other with similar to ours.

We are Aurora Z605 Prusa I3 with Melzi 2.3 running Marlin on Arduino IDE with Pepeter Host software.

We set ours up on the PWM's per the very difficult Chinese documentation, and set the firmware Configuration.h file direction of travel to the opposite of the default settings (boolean), this got all the xyz directions to run in the correct direction, and "zero" at the limit switches.

We have a challenge setting a HOME_POS and can not get it to HOME to an offset from the mechanical switch stops (0,0,0)

Please reply

thank you

Nick