Just won't home

SO, I have checked all my limit switch connections (including the rather untrusted header block connection) and all pins connect to the correct switch positions on all three axes. However, running the homing sequence on easel results in a machine which barely moves at all and sits there in the middle of it’s axes proudly saying that it has homed and easel has moved onto the next step. However the machine has not homed as it used to when I first assembled it. All the motors respond correctly and when I try to carve it starts well, and then inexplicably dives up to the far reaches of the Y axis and tries to force itself apart until I turn the machine off.
Any suggestions?

as an update, Z axis does home, but then the machine doesn’t move to home its X or Y. I have removed the black plastic header and attached the wires directly to the pins on the gshield and have established with a multimeter that all 3 switches should be working. (I’m not a great whizz with electronics but I used the multimeter on the bell setting , put one probe on the white X limit wire where it connects to the gshield, the other on the black at the limit switch, no bell, closed the switch, bell. which I think means that the switch should be working fine)
I’m really beginning t pull my hair out now, not aided I may say but that silly little t.v guy shouting “Hooray! your machine is set-up!” on the screen after every failed home attempt.

PLEASE someone tell me my schoolboy error.

When it goes to home the X and Y does its just jog back and forth ever so slightly?

ever so slightly yes, you can hear the motors jog, but barely any movement of the carriages.

That sounds like it’s tripping the switch as soon as it starts the attempt to zero them. When the machine is successfully zeroed, the axes jog back on forth to confirm the switches have been tripped.

I’d check your wiring for any shorts to ground. Can you post a video of your issue, might help to see what is really happening.

Do you have a serial port terminal program like HyperTerminal, or Putty? Or do you have the Arduino IDE installed on your system?

With one of these programs (or any serial port terminal program) we can interrogate grbl to find out what’s happening in the homing sequence.

Did you get this sorted out @WilliamFeasey?

sorted only by moving the carriages very close to their home position while powered off so that they barely need to move to home. Once hit the switches work fine, but ask them to travel more than an inch or two to reach them and the homing fails.

This sounds like electrical noise generating false trips.

My X and Y axis homing switches do not work at all. In my case, it is most definitely electrical noise. I think that all the wiring should be shielded -AND- properly “drained”. This was not required in the assembly instructions but I think it would greatly improve the success of the switches. I plan on upgrading the wiring when I get a free moment that I’m not carving… maybe when I get an X Controller…

You might won’t to wait on the upgrade. The X-controller has built in low pass filters for the homing switches.

•Built in Grbl CNC Controller. No external controller like Mach 3/4 is required.
•3 axis design
•(4) 4A stepper drivers (Y axis has 2 ganged drivers for X-Carve type machines)
•Microstepping (Full through 1/16th)
•Easy current adjustment via large, well-marked potentiometers
•Automatic idle current reduction independent for each axis
•Internal 24V 400W power supply for stepper motors
•Large internal heatsink and integrated cooling fan keeps system cool at all power loads
•Spindle speed control (0-5VDC PWM or 0-10V)
•Noise-filtered inputs for 3 axis home/limit switches
•Noise-filtered input for Z probe/touch plate
•2 digital outputs to control external items like vacuums and coolant systems
•All inputs and outputs have their own ground terminals for clean and easy wiring.
•Labeled connections
•Rugged latching E-Stop that kills all power
•Feedhold, Cycle Start and Reset (Motion Cancel) buttons on front side (not shown)
•All electrical interfaces use large, detachable terminal blocks
•USB connection
•Heavy aluminum chassis with mounting holes