Pololu Driver Board Rev 2

[J45on]

I consider myself to be rather thick
But I managed to read the instructions and get mine working with no problems

[bdring]

Plot thickens. I just noticed that the square pad on "pin 1" was a red herring. Pololu uses square pins are used to designate ground on this PCB. There are (2) grounds and (2) square pads. I numbered my footprint using standard IC numbering using this figure as a guide.

[BenJackson]

There is a silkscreen of the location of the heatsink and pot, but the pot legend is under the cap now. The heatsink is close to center so I don't think it helps much.

Ohhh I was wondering what that was supposed to be.

[BenJackson]

Can you add the schematic and user guide to the "2.x drawings" page? Easier to find there than in this thread.

[BenJackson]

Just skimmed this entire thread again for the manual to check something and finally found it with Google:

http://buildlog.net/sm_laser/drawings/I ... ide_21.pdf

[bdring]

Sorry about that Ben,

The drawing has been linked on the kits and parts page for quite a while. I was trying to keep the 2.x drawings page a little more 2.x specific. There are 3 different control boards and could get confusing. The real link is here.

http://www.buildlog.net/cnc_laser/erp/g ... ber=A40003

again...since links are all over the place now, the only way to maintain them is to use the get_doc.php page method. This will insure all links will always get the newest version.

[sliptonic]

I've managed to get my driver board mostly working. Homing, motors, limits, safety, all work great. I'm also firing the laser. Of course, to paraphrase The Princess Bride, "Mostly" working is slightly not working. Specifically, I can't seem to control the laser power at all.

My front panel POT reads between 0 and 5V between the wiper and ground (regardless of whether the POT/pwm switch is open or closed) and the switch itself appears to be working(5V on pin 6 when closed). But changing the position of the POT has no effect on the laser output as far as I can tell. Regardless of where it's set, I read 1.71V on the IN terminal of the laser PS.

I'm sure I'm missing something simple but can't seem to spot it. Any ideas?

[BenJackson]

Do you hear the relay click when you flip the switch? If not, check the soldering on the relay and maybe tap the case gently when 5V is applied to see if it will activate.

[sliptonic]

Yep. It's clicking.

[BenJackson]

Then I'd trace the wiper of the pot from the pot to the interface board to the relay and make sure you see your selected voltage there.