Weird problem with 3 axis stepper controller

[Martin_H]

In the builders thread you may have seen my printer part CNC. I built a three axis stepper motors controller using three Pololu stepper drivers, but I am having a weird problem. First some details, I am using one with a regulator and two without.

http://www.pololu.com/catalog/product/1183

http://www.pololu.com/catalog/product/1182

This way I can have one provides logic power for the other two and all three use the same source for the motors. The axis with the driver/regulator combo works finely, but the other two axis do nothing. I double checked all connections and they are fine, and 5 volts is everywhere it is supposed to be too.

Now here's the weird part. I discovered that if I lightly touch either of the other drivers they work fine until I take my hand away. Now that is weird and it means something, but I don’t know what.

[Franklin]

Sounds like you have a floating pin somewhere or a missing ground.

[Martin_H]

Thanks. I think it might be the latter, I will go over the circuit looking for that.

[Martin_H]

I redid the grounds, no luck.

I add some decoupling capacitors to the five volt input, no luck.

I reread the data sheet and found the driver without the regulator requires sleep tied to reset while the other one does not.

So it is a floating pin. Grr argh.