Strange Problem Suddenly

[nitewatchman]

Tonight I was in the process of setting up on a large diameter part and after a layer or so found that I needed to drop z zero a touch. I reset the printer to stop the print and then started to reset z zero. I selected Home Axis on the LCD display and pushed the button and the three axis went down about 10 to 15mm and stopped. Pushed again and the axis again dropped the same amount. Pushed reset and the axis again dropped the same amount ant the Rambo then reset.

Tried the universal reset and powered of but this made no difference. After repowering pushing either Home Axis or reset simply causes the three axis to travel down. Everything else seems to work okay.

I thought I remembered seeing a post with this problem but have been unable to find it. Anybody have any ideas?

[Eaglezsoar]

Sounds as though an endstop switch may be giving you some trouble.
What does a M119 return?

[guanu]

one of two things can cause this. either all 3 endstops unplugged or are triggered (unlikely), or you reset z0 at the top of the towers.. turn the machine off, put the nozzle up towards the top by hand, on the lcd go to advanced - calibrate z - click home all... if it just moves down a few mm again, go to z position... if it says it is currently at 0, turn the knob counter clockwise and bring the nozzle down about 100mm or so, click the knob, go down to set z=0 and click... then click home all... it should home normally... then go back to z position, and bring it down where you want the nozzle to be for z0, click, go to set z=0 and click.... you should be back in business..

the good thing about doing everything from the lcd is it allows you go to beyond 0 when setting z position where software wont let you go negative.. when I calibrate and set up machines I only use the lcd... and only use software for adjusting horizontal radius in the eeprom... otherwise I never use the software. Of course I never use a sheet of paper when calibrating because I dont like the one tower at a time method... but after you've calibrated over 600 machines you find better ways to do things lol

Guanu

[nitewatchman]

You must have stayed at a Holiday Inn last night!

I had checked the end stops for function but odds of all three failing at the same time were right up there with the Rambo being struck by a micro-meteorite, and I didn't check for that.

Setting zero on the home switches makes sense. Machine has to back off to clear the switches to complete the home cycle and since the height offset is never loaded no matter where it ends up it is still a zero and has to back off again. It would keep doing this until it reached the earth core.

Thanks for help with the cranial extraction. Everything is once again in harmony.

nitewatchman

[bot]

Guanu is a smart cookie. The LCD is useful for measuring the gap at any point, not just x0 y0. I barely ever hook up the USB.