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I'm having trouble with homing UCCNC, ETH400, DIY router. For the first few months the homing worked fine, but now I have more and more intermittent trouble with homing the z mostly and sometimes the y (gantry) axis. The homing will go up against the limit switch and instead of bouncing back, it will just sit there tripping the limit switch and putting the UCCNC into reset logic. X axis has always homed fine.
I've tried setting the homing bounce setting to a few ms but that didn't help.
Any suggestions?

What if you set the debounce to a big value?

Still doesn't work and it bends the limit switch.

Set the de-bounce to zero and make sure the homing speed set slow enough as to not over-run the limit switch. Make sure the X and Y axis home pins input numbers aren't set the same values. Best way to check is move the axis to the middle of travel then do a home command. Manually trip the switch with your finger and see what happens. Sometime switches with large mechanical deadbands can cause overrun problems. Could also be a intermittent switch problem.

I set the homing speed slower and I think that solved the problem. Time will tell. Thanks for the help.

Sorry to say, the speed didn't fix it. After a day of use, it seems if I trip the x limit switch (I'm using the limit switches for homing) when z approaches zero, it will home. The x switch is the first on the cable with z being the last. It's a shielded cable.
Does this make any sense?

You should debug by selectively removing potential problems to see if anything changes.
If you have a VFD try unpowering it and doing a long run.

I think you are chasing electrical interference and VFDs are known to cause it.