RAMPS 1.2 Missing Steps

I have been working to upgrade my electronics to RAMPS 1.2 with a Arduino Mega. I have everything wired up, Sprinter loaded, and Prontface running on my computer.

Everything looks good, computer connects, and I can send steps to the drivers. However when I manually send +1 steps maybe 20% of the time it fails to turn (just makes noise), and +10 never works. I lowered the drivers current limiting and have inched it up almost all the way, but it appears to have no effect, and I would not like to turn it all the way and burn out the drivers. I do have heatsinks attached to the allegro chips.

So, any thoughts as to what might be causing this? I am using a computer PSU, so it should be a reasonably clean DC current going to the steppers. The only thought I have is I am connecting the stepper carriers through a breadboard which may introduce noise, since I did not have female headers.

Any help would be appreciated.

---

-----------------------------------------------
[mfsamuel.blogspot.com]

I can think of three possibilities:

1. The feed rate or extrude rate in the case of the extruder is too high. Some versions of Pronterface set a very high default feed rate for the Z.
2. You were turning the wrong trimpot. This happened to me with RAMPS 1.2 since the arrangement of the Pololu carriers was not what I expected.
3. Your axis is binding. Does it move freely if you disengage the belt and motor? It should.

I had similar problems with sanguinololu, and solved it by using a known-to-work usb cable directly from a motherboard port, and bumping the baud rate to 250k, which I was told is better for sanguinololu. I don't know if that is true for ramps though.

Also breadboards connection do give room for a lot of weird behavior.

---

--
-Nudel
Blog with RepRap Comic

My Baud Rate is set to 115200 in both prontface and sprinter.

1. The feed rate or extrude rate in the case of the extruder is too high. Some versions of Pronterface set a very high default feed rate for the Z.
would this matter for a single step?

2. You were turning the wrong trimpot. This happened to me with RAMPS 1.2 since the arrangement of the Pololu carriers was not what I expected.
I am testing 1 motor at a time not in the printer, so I am sure I am using the correct drivers

3. Your axis is binding. Does it move freely if you disengage the belt and motor? It should.
I am testing 1 motor at a time not in the printer, so there is not axis to bind.

Any other thoughts or do I need to resign myself to the fact the breadboard is the issue? I would obviously rather not rebuild this circuit.

---

-----------------------------------------------
[mfsamuel.blogspot.com]

OK. Ignore most of what I wrote then. Note that +1 and +10 means 1 mm and 10 mm, not steps. Are you sure about your configuration.h?

I'll check this out. I am using the default mm/steps, and no micro stepping, so that might cause issues. I incorrectly assumed that the +1 was steps not mm.

---

-----------------------------------------------
[mfsamuel.blogspot.com]