<p>My custom 3D printer prints everything inverted. I guess this is a homing problem as the motor moves in correct direction.</p>
<p>In Pronterface,</p>
<ul>
<li>if I press -Y — bed moves forward (towards the Y endstop)</li>
<li>if I press +Y — bed moves backward (away from Y endstop)</li>
<li>if I press -X — hotend moves left (towards the X endstop)</li>
<li>if I press +X — hotend moves right (away from the X endstop)</li>
</ul>
<p>on RAMPS 1.4:</p>
<ul>
<li>X endstop is connected on the 1st pin</li>
<li>Y endstop is connected on the 3rd pin</li>
<li>Z endstop is connected on the 5th pin</li>
</ul>
<p>(Pin 2, 4 &amp; 6 are not used (are these for MAX_ENDSTOP ?))</p>
<p>Below is my Marlin config</p>
<pre><code>#define X_MIN_ENDSTOP_INVERTING true // Set to true to invert the logic of the endstop.
#define Y_MIN_ENDSTOP_INVERTING true // Set to true to invert the logic of the endstop.
#define Z_MIN_ENDSTOP_INVERTING true // Set to true to invert the logic of the endstop.
#define X_MAX_ENDSTOP_INVERTING false // Set to true to invert the logic of the endstop.
#define Y_MAX_ENDSTOP_INVERTING false // Set to true to invert the logic of the endstop.
#define Z_MAX_ENDSTOP_INVERTING false // Set to true to invert the logic of the endstop.
#define Z_MIN_PROBE_ENDSTOP_INVERTING false // Set to true to invert the logic of the probe.

#define X_HOME_DIR -1
#define Y_HOME_DIR -1
#define Z_HOME_DIR -1

#define INVERT_X_DIR false
#define INVERT_Y_DIR false
#define INVERT_Z_DIR false
</code></pre>
<p>I have attached 3 photographs.</p>
<ol>
<li>Shows the Home position of hotend. Y Motor on back and Y endstop at front.</li>
</ol>
<p><a href="https://i.stack.imgur.com/M4Gcr.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/M4Gcr.jpg" alt="Home position of hotend" /></a></p>
<ol start="2">
<li>Shows inverted print.</li>
</ol>
<p><a href="https://i.stack.imgur.com/9SRBZ.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/9SRBZ.jpg" alt="inverted print" /></a></p>
<ol start="3">
<li>Pronterface screenshot (shows actual G-code file)</li>
</ol>
<p><a href="https://i.stack.imgur.com/4ru5r.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/4ru5r.jpg" alt="Pronterface screenshot" /></a></p>
<p>I tried flipping the motor cables, but that inverts the motor direction
I also tried INVERT_Y_DIR true, but no luck.</p>
<p>Please help me. What am I doing wrong?</p>

[{'answer_id': 16104, 'author': 'Rykara', 'author_id': 16811, 'author_profile': 'https://3dprinting.stackexchange.com/users/16811', 'pm_score': 3, 'selected': True, 'text': '<h1>Heater polarity doesn\'t matter</h1>\n<p>The heater cartridges are just large resistors and so polarity is irrelevant. Either can be positive or negative.</p>\n<p>You can extend the leads by cutting and splicing in ~20 gauge wires* to a two pin JST connector line you suggest.</p>\n<hr />\n<p>*<sup>At 24 volts and 30 watts, you need <a href="https://www.platt.com/CutSheets/Multiple/AWG%20Conductors.pdf" rel="nofollow noreferrer">wire that is rated to carry at least 1.25 amps</a>. The US National Electric Code dictates that this should be 20 gauge wire, but their standard is very conservative. Since you don\'t need to adhere to NEC codes, you could get away with something thinner (ie higher gauge number).</sup></p>\n'}, {'answer_id': 16107, 'author': 'Perry Webb', 'author_id': 15075, 'author_profile': 'https://3dprinting.stackexchange.com/users/15075', 'pm_score': 2, 'selected': False, 'text': "<p>1 meter puts you far enough away from the heater than you don't need high temperature wiring to extend it.  The larger the guage(e.g. 20 guage) the less resistance you will add to the heater circuit.  This doesn't matter as long as you can still achieve your maximum temperature (if you can still achieve the same current without maxing out your voltage on the heater).</p>\n<p>Your sensor is where added series resistance is critical. Series resistance to the thermistor will give a negative error in the temperature.</p>\n"}]
['https://3dprinting.stackexchange.com/questions/16113', 'https://3dprinting.stackexchange.com', 'https://3dprinting.stackexchange.com/users/27919/']