RUMBA problem once print finishes (head crashes into printed piece)

I've had this happen twice now. The printer completes it's print and then the screen shows "Waiting for user input" while the head starts to move down. First time I wasn't next to my printer and came into the (still heated) hot end buried deeply into my printed piece. Second time I was standing next to it and it did the same thing. I kept hitting the z endstop switch, but it didn't stop. After it broke my piece in half (a problem superglue thankfully fixed) I hit the power switch.

I'm using the config files from makerfarm and they all look fine. (Turn off heat, home x axis, home y axis.)

I can't figure out why it's dropping afterwards. Any suggestions of where I should look first?

No knowledge of Rumba here but if you're Z axis is heading down for a crash, remember you can just grab it and lift it off the nuts while you figure out what's going on or get it shut down.

Check your ending gcode?

I already mentioned that I checked it and it was just the basic endcode.

Code:

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G1 F1800.000 E0.09042
G92 E0
G1 Z147.200 F6000.000
M107
M104 S0 ; turn off temperature
G28 X0  ; home X axis
G28 Y0  ; home Y axis
M84    ; disable motors
M190 S0 ; wait for bed temperature to be reached

---

How tall is the part? If your part is taller than 147.2mm (~6in) wouldn't this line bring the head back down?

Code:

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G1 Z147.200 F6000.000

---

The last layer is G1 Z146.600 F6000.000

So it shouldn't be a problem. The thing that gets me is that it says "Waiting for user input" while slowly attempting to crush my print.

Oh, I thought for some reason that was just the end code, but it has a few lines of part code as well.

It sounds like (from the OP) the head is not homing in X/Y nor is the nozzle heat turning off. It's almost like the firmware sees some fault condition and goes in a crazy direction before even getting to those gcodes. Does the fan turn off (M107)?

A quick search of Marlin firmware does not show "waiting for user input". Does this show on the LCD or the computer?

Does your control program (e.g. printrun, cura, octopi etc.) show anything in the console (or maybe you are printing from sdcard)?

Sorry, I'm grasping at straws. Don't see anything interesting in the gcode.

yeah, I didn't see anything either. I don't have a fan (hexagon print head) so maybe it see's the "turn fan off" and faults because there is no fan to turn off?

edit: Just to clarify, I have a fan but it's connected directly to the 12v line, not to the rumba board.