Sudden two axis death?

[Louis]

Hello!

I fired up my LoboCNC today to do a small project (it has been working flawlessly since I built it).  When PSCNC started, it found all three motors and all of them did the little initializing jerk.

Then, only the Y axis moved for the homing process.  I rebooted and unplugged everything with the same results.  So far I've found the following:

• The Z and X axis twitch a tiny bit when PSCNC tries to home them--it's almost like they overtorque in place immediately and it senses the current position as the "limit"
• When rotated manually, the inoperative Z and X axis motors feel about the same as the Y axis...maybe slightly more pronounced cogging, but nothing significant.  Unless...
• When rotated QUICKLY, there is a lot of resistance on the Z and X motors (the Y one feels the same regardless of speed).

My hypothesis is the Z and X axes in the controller are toast (something is shorted if the Z and X motors are tough to spin quickly).

What's my next move?  Is it worth swapping motor leads around and seeing if the problem moves to follow?  Can I get another controller?

Thanks for your help!

[Louis]

So, swapping out the A3967 driver chips for the failed axes was the fix--thanks Jeff.

If this ever happens to you, you'll need Digi-key P/N 620-1140-1-ND and a hot air rework station--it's a quick job.