Stuttering and Unpredictable Z axis

[EBankert]

I have been having a problem with the Rostock Max V2 lately, but no matter what I try, I can not get it to work. The Z axis will vibrate up an down about a 1/4 inch repeatedly while homing and slowly move downwards. In addition, the motor goes up 50% of the time and down the other 50%. It is completely unpredictable. Here is everything I tried and the result.

Securing the connections- No effect
Replacing the Z axis motor- No change
Switching the Z and X axis motor- Not the X axis messes up
Complete driver reinstall and reconfiguration- Nothing
Increasing Current- No effect and the board emits a high pitched tone
Changing microstep- Nothing

I am out of ideas. I think that it could be the board. Any help is appreciated!

Eric B

Sidenote: This printer was given to my high school by a local college. They said it was working before, but it stopped printing, so they gave it to us to fix. I have no idea when it was shipped to find the correct manual, but I don't think that matters. I just used the third one.

[IMBoring25]

If switching the motor switches the symptom, it is the motor or its wiring.

[EBankert]

I put in a brand new motor and it still acted the same way. Switching the Z and X axiz connectors (on the board) make the X axis have the same behavior. I think it is a software issue or a problem with the control board.

[joe]

There is a way to repurpose the the second stepper extruder driver (E2). The z motor would then plug into the E2 socket on the Rambo.
It is a fairly simple firmware change , I've done it myself. Do a search and you should find lots of info on how to do it. I am pressed for time the next few days or I would find it for you.

[lightninjay]

Unplug your endstop switch wires from the RAMBo, bring the carriages low on your towers, then try to home, but shut off the machine before it gets to the switches and see if the behavior still occurs on the rise up.

If this solves your behavior problem, it means you are experiencing interference from the stepper motor drivers at some place in your printer, crossing your endstop wires and creating jitteriness.

[EBankert]

Thank you Joe!
The fix worked fine and now the axis moves without problems. Now I am having a problem with the knob on the controller. I can push the button to get to the menu, but when I turn the knob to scroll thru, the printer homes and resets. I have no clue what this is. The ribbon cables are fine and I made no changes to the code. Any help is appreciated!

For Clarification:

The status reads "Home Delta"
Then "Resetting/E-Stop" flashes for a moment. Then it is back to normal

[geneb]

I bet the adapter board for the ribbon cables to the rambo is off by one pin.

g.

[EBankert]

The adapter board is plugged in fine. I tested the ribbon cables and checked the main board for shorts. I found nothing. This problem has remained through numerous firmware re-installations, so I think it is hardware based.

The controller is a RepRapDiscount board with a 20x4 LCD display

[Mac The Knife]

The adapter board is plugged in fine. I tested the ribbon cables and checked the main board for shorts. I found nothing. This problem has remained through numerous firmware re-installations, so I think it is hardware based.

The controller is a RepRapDiscount board with a 20x4 LCD display

When you stated that the printer was a Rostock Mac V2, it's ASSumed that the controller is a RamBo board.

[EBankert]

It is a Rambo Board (Ultimachine)

[Xenocrates]

It is a Rambo Board (Ultimachine)

I suspect in this case the LCD controller (Which is a reprap discount board), and the actual controller being a Rambo caused some confusion due to the wording used, since Reprap discount produces some number of printer controllers as well. Darned technical terms, having only one good one for the two different MC's in the printer.

It sounds like the front panel button may be malfunctioning to me, as it is sometimes set as a pause, and other times as an E-stop. Is the button cover recessed and caught on the panel (As happened to me anytime I used it), and does the button click and recover reasonably?

[geneb]

I'm sure it's hardware based. I bet the interface connector is off by one pin.

g.

[EBankert]

The button was clicking fine, it just seems to be when I turned the knob.

EDIT:
So I flipped a cable, because whoever put the thing together attached the lead on backwards, and now the lcd is displaying this cycle of messages:

-Repeties 091S
-ROSTOCK MAX
-
-SeeMeCNC

then it displays the "ready" screen with the temperatures and flow rate values

And the control knob does absolutely nothing!
Still broken...