Off the rails... again!

[rsorensen]

Could use some help on this one. My PRT v4Gg machine has dropped off the rails a number of times in the last couple days. I thought I was chasing a driver problem on one of the X steppers so replaced that driver (I could see a noticeable shudder/hear a not-right noise when it would start/stop moving in the X direction). In the process of replacing the driver I also found a loose wire on the same motor ... maybe that driver isn't toast after all?

Anyway. With wiring repaired and driver swapped out I was 'test driving' it. Shudder gone, noise gone, back to quiet, smooth operation, when suddenly it went off the rails (X rails). Got it back on, ran it some more, off the rails again. Got it back on, ran it some more (discovered my proximity switch wiring problem that I'm chasing), and off the rails. Again. This is getting frustrating!!! Where do I start looking?

[evan]

Sounds like something is out of square. Check the Gantry hasn't racked, isn't square to the rails. Also be sure the rails are dead parallel to each other. Drop the pinions off the racks, move the gantry up and down the full length of the rails, making sure each wheel is fully engaged along the full length of the rail. Check that the pinions and racks are fully engaged - and square to each other.

[phil_o]

If you haven't called Shopbot tech support you should. They are very helpful.

Phil