Tronxy p802m Z-axis issue goes below the plate on home

Hello,
First of all if this is in the wrong place I apologize. Second I am a newbie trying to learn. The printer is running Merlin 1.0 and I trying thing using the LCD screen. When I click on return to home the X and Y axis appear to go to the right place. The Z-axis keeps going down and will crash into the plate below. The printer has a self leveling attachment and the red light does come on but the z-axis keeps going down. I made sure all the motors and wires are working and have made no changes to the firm ware other than using the LCD Screen

What am I missing
Any help would be appreciated.

Edited 1 time(s). Last edit at 04/13/2017 03:04PM by Timb001.

Hi I'm new to this as well.
Does your X Y Z have stop switches? if so you need to adjust the Z stop a little higher.
Adrian

It only has micro switches for the X and Y. The z axis has no switch and looking for someplace else to stop it.
Frustrating.

Is the sensor positioned over the bed when it tries to home Z.

If you move the Z axis well away from the bed (say Z 150) then while it homes Z does it stop moving if you manually trigger the sensor with a metal object.

I unscrewed the plate and lifted it up to the sensor. The little red light came on but it kept moving down

which means the sensor is plugged into the wrong place or the firmware is configured wrongly for your hardware.

Or passably a board fault...

What controller board do you have ?
Was the firmware pre-loaded onto the board or did you upload it ?

Sounds like the sensor is either connected to the wrong endstop input or wrongly configured in firmware.

I believe it is a Melzi board. Everything came preloaded and I have not touched touched it at all. I have checked the wiring five times and according to the diagram it is the correct place

Firm ware is Merlin v1.0

With no enstops activated send a M119 code to read endstop status,
then resend M119 with the Z probe activated. post results shown in log

Sorry have been out of town. Log Attached.

1 - Issued M119.
2. - Homed Printer and as z axis was going down issued two more M119. They ended up in a pending status.

Maybe easier to use a regular micro-switch for the z-axis stop?

All,

I was able to solve the issue. Went back and looked at everything and I noticed on the plug that fits into the boards the middle wire pin connector was sticking up further then the others. Pushed it in to match the others, plugged it back in tested.
Performed the homing function and z axis was all the way up. Placed a piece of metal on it and it stopped. Tried this several times and ir worked each time.. Now I have to calibarate everything to work with the plate.

I believe I am well on my way to the first print.
I want to thank you all for the support and help