z axis frying an egg

[cidteach]

Hey guys
have a pretty good shape and lightly used bpt ezplus cnc mill. have been getting random z dac overflow errors when trying to run programs for students to learn setup/ dry running code. I popped the face open and found a faulty limit switch. swapped it out and still get a overflow error. the z axis motor got so hot that i couldnt touch the casing. it smelled like god knows what in the shop. weird this is, once cooled down i can easily turn the motor by hand. the z axis is not jammed up at all - also move it easily by hand. i have no idea if the servo motor is shot, the encoders are bad...

any help is much appreciated.

[Al_The_Man]

It should not be counterbalance problem on a Z quill machine, so other than mechanical binding it would most likely point to too high a PID gain.
Al.

[cidteach]

can ya run that by me again....where can i go to play with the pid #'s. I have never had an issue with this before (besides a z quill crash from a careless student in the past).
is there a directory, way to access this info?

love this place.
Thanks