stepper motor only turning in one direction - was fine - pololu

Hi All

I am stymied.

I am using a pololu driver to drive one of my stepper motors and all was working fine.

Now regardless of whether I nudge the motor up (+ direction) or down (- direction) it only moves down. It moves down even when I nudge it up!!??

Can anyone please advise?

I have a heatsink attached to the pololu chip. I had the machine on for a few hours tonight while testing the temperature stuff on my hot-end without moving the bed.

Now I tried moving the bed and the above problem occurs.

I have rebooted my PC and shut down and restarted the printer a few times.

I have tried driving a different axis which works fine.

I have tried driving the pololu from a different axis which fails.

The g-code sent to the printer is fine.

Anyone have any ideas? Have I somehow fried my pololu chip? All wires are still connected...

Man - this is an endless battle

Cheers

sounds like your direction line isn't connected properly. hook a logic probe or multimeter or even an indicator led to it so you can see if it's going high or low in response to the direction changes

---

-----------------------------------------------
Wooden Mendel
Teacup Firmware

Thanks for that Triffid.

I know the signal is being sent from my motherboard so it may be a loose connection on the stripboard hosting the pololu driver.

I do appreciate you giving me a place to look. I had no clue where to go.

hmm..

unfortunately it is not the DIR signal - That is being flipped when I change direction.

Anyone have any other ideas?

Hmm...

I had removed the chip so I could insert my probe wires (connected to an LED and resistor) to check the change of direction. This showed there was a change in the DIR pin.

I plugged the pololu back into my stripboard carrier thinking I would check the back of the signal to see if the connection was dodgy. Testing it worked!! Wohoo - obviously somehow the connection between the male pin on the pololu board and the female header on my stripboard went south.

Phew - working now.

I'd double check/redo the soldering of the stripboard header and the headers on the Pololu's, just to be sure.

if you have another pololu driver on your board, i'd try switching it with the broken one, that way you can find out if its your motherboard or the pololu itself thats broken.