i would use an ohmeter, with power off, and test all of the home position switches to see if they are changing state from open to closed (or vice versa) when depressed. disconnect the switch, and insert ohmeter. you can even push/pull the axis toward the home position to watch the switch change state. check the mounting screws to see if they are tight. possibly one of the switches was loose and has moved, and the gantry travel is not engaging the switch far enough to change its state. your table may have a bracket that engages the switch as it travels, maybe the bracket became loose and moved.
you can also watch the state of the switch with a voltmeter while the machine is running. caution required here because you will be measuring live voltage, and the machine will be moving. try to find a safe place to insert your meter probes, and measure the voltage coming out of the switch, unsure if you will be measuring dc or ac on that machine. either way, the voltage should change as the machine actuates the switch near the end of its travel.
you can also watch the state of the switch with a voltmeter while the machine is running. caution required here because you will be measuring live voltage, and the machine will be moving. try to find a safe place to insert your meter probes, and measure the voltage coming out of the switch, unsure if you will be measuring dc or ac on that machine. either way, the voltage should change as the machine actuates the switch near the end of its travel.