XYZ

Got a good chunk of the electronics built this weekend. The power/comms board and all three stepper drivers are working. The only difficulty I ran into was that, following the build/test instructions on the reprap site, I found that one test failed. Turned out it was because the sync line was floating. Once I got around that, though. everything else was fine.

Had all three motors running at once. Managed to crank up the speed pretty high before they started to slip.

Oh, I did notice a minor problem with the BOM shopping list generator. Looks like the large heatsink and small heatsink Mouser part numbers are swapped. I ended up with 5 small and 2 large instead of the other way around.

Overall, though, the boards were remarkably easy to assemble.

The only place where I deviated from the intended design was where I ran the 12V power to each board directly from the power supply, rather than through the power/comms board. With the power supply I'm using, it's a bit more convenient to do that.

Steve,

Not nice to hear about the heat-sink thing. I just ordered ALL of my electronics parts from Mouser! :-( Oh, well. At least it isn't more than just a couple things that are messed up.

Good work!

Demented

i'll double check that. gotta make sure the BOM is correct. also, i gotta put the 10nF capacitor in there for the extruder board as well.

Yeah, I just noticed that one myself. As luck would have it, I'm fresh out of 10nF caps. Closest I've got is 50nF. Might have to scrounge one off an old circuit board.

And, if you want to get really picky, the screws and nuts to mount the heatsinks are missing too. Of course, I'd have to question the nerdocity of anyone who doesn't have a few 440 (or metric equivalent) screws lying around.

okay, i updated the part lister db. both the capacitor and the heatsinks have been fixed. yay!

screws have yet to be sourced, but i imagine i'll get around to it someday. agreed on the nerdocity front

Mouser:
Nuts: 5721-440-SS
Screws: 5721-440-1/4SS
Both are 100 per pack, which is admittedly a bit excessive, considering you need, what, seven?

Small Parts Inc has (AFAIK) the metric equivalent:
Screws: MPX-M03/06P-25
Nuts: HNX-M03-25

The current BOM already includes some M3 nuts, so maybe that's the way to go.

cool, i'll add those into the BOM here soon.

I'm assuming a pan-head 6mm M3 screw will fit a heatsink but I don't have any handy. Can anyone confirm?

Best way is to simply put the heatsink in your pocket and go to the hardware store. I've found that #4 screws and lockwashers work great with the heatsinks you buy at Radio Shack.