Bed Auto-Home fails more than not

I’ve had this unit for a while and this has been a fairly regular issue to the point I put it on a shelf and moved on to other printers. Recently decided to bring it back out and try my luck with it again, seems it’s still doing the same. The extruder homing works correctly, but the bed regularly fails the auto-home process, regardless of what position it starts in. Sometimes it just jitters and fails, sometimes it will move nearly the full stride, and still fail. Sometimes the homing sequence runs, the bed moves back, doesn’t hit the switch, but the machines ‘thinks’ it did and uses it’s last position as it’s starting position and skews everything by that much. I’ve tried running both the 1.0.9 and 1.1.0 firmware, along with ‘updated’ firmware from various authors thinking maybe it was a software bug, the problem is still persistent leaning that it’s a hardware issue, either a wiring issue or something on the main board (though that’s not my field, so uncertain).

Anyone running in to this issue, and anyone having this issue found a way to reliably solve it?

Hello JZmatrix & welcome to the forum!
Your SV04 seems to struggle with a hardware issue. You may want to:

  • check that all belt gears on the stepper motors are connected firmly
  • check all endstop switches using a multimeter
  • check all endstop connectors on the motherboard & left gantry breakboard
  • check the wiring between endstop switches and motherboard connectors using a multimeter.
    Checks should include looking for faulty solder joints, weak cables, loose connectors and observing changes in electrical resistance when manually wiggling the cables.

If the above did help to locate the error source you may want to check wiring & connectors of the CR touch sensor, in the same way.

Good luck!
Björn