Help with Stepper motor, one works, other doesn't

Hi all, I've got a 4wire bipolar 20 step stepper from a floppy drive, I have it running nicely using an L293D and the stepper library running through the standard bipolar wiring diagram on the arduino tutorial. Both of my enable pins are tied to arduino +5v, everything works nicely for this stepper.

I've also got a 48step bipolar pulled from a printer, its rated at 24V, so before wiring up I tested the motor using 4xAA batteries (4.8V) and a 12V battery, mainly to see what kind of holding torque it had at lower voltages and if it would even respond at ~5V, both were adequate.

As I understand things to put 12V through the L293D I put + from the battery to pin8 VS on the L293D, where exactly does battery - go? I've tried multiple points on the l293/circuit, 4,5,12,13, the - rail on the breadboard before and after any other connections to - rail, I'm farily stumped as to what else to try. I don't get any response from the stepper at all, no chatter, no movement at all. the l293 circuit is still working correctly from the arduino end as each input pin on the l293 has a led attached that indicate which coils are energised.

any clues as to what I'm doing wrong?

so were you powering the l293d and arduino off separate power sources? if so they may need to share a common ground meaning the ground of both power sources needs to be connected with a wire.

for my configuration that works with the floppy driver stepper the arduino is supplying both logic and motor voltage. For the 2nd motor that doesn't work, I am using 2 supplies, arduino is providing the logic voltage and the 4.8V/12V battery is supplying the motor voltage. and at any of the points I have have mentioned 4,5,12,13 are all tied to arduino ground, + directly to the arduno gnd too. no joy.

see if the floppy stepper works with the external power also first. i have a feeling its a power supply issue.

I've got the a unipolar stepper motor working using 12V into a uln2003, I'll re-do my l293D circuit and see how that behaves now I know that things are fairly sound.

Either my wiring is wrong or this is a geared stepper???? It's supposed to be a 64 step motor, but it takes 2048 steps to do a complete revolution, I don't see it doing anything odd in its turning, doesn't sound like its chattering at all, it doesn't seem to miss any steps. would I be right in assuming its a geared stepper?

It mentions a 64:1 ratio too, but 64*64=4096 not 2048 :/

does anyone have any ideas?

Either my wiring is wrong or this is a geared stepper????

Not sure of your wiring, but that is definitely a geared stepper. Notice how the output shaft is offset from the center of the motor case. I suspect it's a 64/1 geared ratio


hmmn, looks like I have a super accurate / super slow stepper then :) It does turn very smoothly so I think the wiring is fine, seems to have constant torque through all steps but at such a super fine resolution its hard to 'see' an individual step.