No power on the y-axis pololu board

Hi everyone,

Forgive me if this has been answered somewhere else but I’m very new at this so need some help.

Have basically finished my build and sorting out the electronics and motors.
On 1st connection of all the motors to my Sanguinololu 1.3a, all motors functioned, except for the 1 connected to my y-axis. Completely dead.

Tested and adjusted the voltage on all the Pololu boards but no voltage showed on this particular board which is connected to the y-axis. Moved the Pololu board to a working x axis to test the board and the motor continued to function perfectly… So nothing wrong with the Pololu board then. Also tested the motor on a different axis point and no problems.

Tried to see if I have continuity between the step and dir pins on the pololu board in the y-axis and the Atmega 644P chip (pin 28 and 29 I think) and it seemed OK. Don’t know if this really proves anything though.

I’m a complete newb with this so don’t really know why it seems as if there is no power being let through to y-axis pololu board. Can I test for this with my multi meter? How do I do that? Would I be able to test the continuity for this between the power access point and the pololu voltage points? Thought that might be a way to see of the solder point was sound.

Could this be that Atmega pins are not assigned correctly for supplying power to the Y-Axis? How do I check this and how would I fix this? Does the Atmega chip even control the power flow to various axis points on the Sanguinololu board or does the power supply come directly from power cable access points. Like I said, a complete newb.

Using Sprinter firmware by the way.

Any help would be much appreciated.

Regards

rdp

Edited 1 time(s). Last edit at 11/14/2012 03:13PM by ruandp.

> no voltage showed on this particular
> board which is connected to the y-axis.
No voltage where? The power pin, the current-setting pot, or the motor output?

> Would I be able to test the continuity for this
> between the power access point and the pololu
> voltage points?
Yes, and good idea. (A Polulu has two power supplies, logic (usually 5V) and motor (usually 12V); check both.)

> Could this be that Atmega pins are not assigned
> correctly for supplying power to the Y-Axis?
Yes if you mean no power at the motor output (check that your firmware is configured for Sanguinolulu), no if you mean no power at the Polulu's power pin. (The ATmega can turn the whole power supply off if it's an ATX (PC PSU) type, but as your other motors are working, it can't be that.)

I've done some additional testing to test the continuity and cancel out bad solder points causes and it looks to be ok frankly.

VDD shows connected with the other boards, Gnd points also seems to be continuous to other GND’s on the Sanguinololu board, but frankly I’m don’t really know between which points exactly I should be testing.

Also the 5V and 12 V connection points seems to be continuous from the ATX PSU point and the USB point and receiving power.

Thing is if I try and measure the current between the turnpot and the ground connection there is nothing there. So it looks like the current is not allowed through somehow or I still have a short somewhere. Would a short somewhere not have messed up the continuity and power tests?

Double checked my firmware (Sprinter) and uploaded again making sure that Sanguinololu is chosen but no change. Don't know enough to try and reassign the pins but I need to try something.

> Thing is if I try and measure the current between
> the turnpot and the ground connection there is
> nothing there.
I think you should be measuring voltage, not current.

Also try checking continuity from the Polulu's enable pin to the ATmega.

yes sorry, mistype there. meant to say no voltage between these points.

also tested the continuity between pololu's enable pin and Atmega (pin 20 ) and that check out fine as well.
looking to be more and more a firmware problem.

any suggestions what pins I might need to reassign in sprinter for z-axis and what alternate pins are open in to use?

thanks for the help btw