DRobs86 wrote:For the record people need to be careful adjusting those polulu drivers. Luckily I have not done it but I've heard of a lot of people destroying them by shorting them.
Also... Not sure if you ended up sending this to cov but you may want to check your fuse on the protoneer shield. They are often cheap Chinese clones. Mine was and the fuse from motor supply to ground blew dang near immediately. I checked for problems extensively and just ended up putting a reasonably guaged jumper across the fuse and have since cut dozens and dozens of pieces with no problems.
And the winner is...... DRobs86! I wired across the fuse on the CNC shield as you suggested. Initially I was worried because there was a minor explosion on the board when I plugged the power in, but lo and behold the steppers could be moved!
I then set the href voltages on the drivers as the Pololu website says. I found this incredibly difficult to get accurate. I was after 0.75V for each one, but ended up with a range of between 0.73V-0.78V for all 4 drivers. Anyway it all appeared to be running smoothly so I tried the 'Hello World' exercise again. Previously the S and H would draw correctly then it would mess up the rest of the letters, but after setting the correct voltages the whole thing worked first time!
I'll try cutting something tonight for the first time and see how that goes. I've also ordered a new CNC shield and drivers - just in case.
Thanks for all your help guys. I'll write up an instructable for how I see how to get the electronics running first time on these machines.