light on sensor works but Z probe not triggering z-min in firmware

I have followed the wiring directions from this page: [forums.reprap.org]

I am using a 10k and 20k resistor.

The light on the top of the probe is lit when in close proximity to the aluminum heat bed as seen here: [drive.google.com]

However, the light turning on does not equate to triggering the z min in firmware. I have tried repetier and marlin. I Have tried settings for mechanically open, mechanically closed, switch open, switch closed in both firmwares. All with the same results. What am I missing here?

Printer:
MKS Base V1.2 (Essentially ramps 1.4)
LJ12A3-4-Z/BY inductive sensor
Mendel Prusa i3

Using M119, is it changing between open and TRIGGERED when metal get close to the sensor?

Not all inductive sensors work on 5v.

Another way to make it work is to use a relay. I have a sensor connected via a 12v relay board on one of my printers.

M119 does not show triggered. That's the problem. The light on the sensor works. Firmware never registers the event. I originally tried it on the 5v rail. I was getting the same result. Then I attached the resistors and attached v+ to the 12v rail.

If you connect a wire between the Min Endstop pin and the ground, does that signal get through, M119. If not you have other problems, if so then your switching is not good enough. Personally I don't like the resistor voltage divider, you need to know the exact impedance of the sensor to calc out the R vales properly. What I did was to power up me sensor on the 12 volt rail, making sure the sensor can operate at that voltage and then route the output signal through a simple 3 pin voltage regulator. The input voltage of the reg is something like 10 - 30 volts and the output is 5 volts, perfect signal every time and they are cheap to buy.

After fiddling around with the settings for a couple hours my buddy and I have come to the conclusion that there is no way to disable the pullup resistor. The state is always held high. I did a little more googling and found this: [forums.reprap.org]

With out desoldering the resistor, is there any thing else that I can do to fix this? There does not seem to be a schematic for the MKS BASE V1.2.

I took an image of where I believe the resistor to be but im not sure: [drive.google.com]

Looking at the image, it looks like there are no resistors, just solder pads. Any help would be appreciated.

Edited 1 time(s). Last edit at 04/10/2016 01:04PM by peoplenamed.

I have a 5v regulator lying around. I will give this a whirl. However, during our tests, when the light on the sensor came on we were reading almost 6v. When the sensor was pulled away from the board the light went off and the voltage read 0v.

Have you found a solution? I'm experiencing the exact same problem and have been trying to get my head around it for hours now.. I'm ready to desolder the resistor off the board but can't find it.. Maybe thats the problem?

Same problem here works fine on a ramps board but not on the mks gen 1.4. Anyone come up with a good easy fix please PM me!!