Spindle shutdown on an '81 Kitamura Mycenter 2 w/ Fanuc 6m-b
Here's the scoop:
I began drip feeding a program (I've run 30 times prior) to my 1981 Kitamura Mycenter 2 w/Fanuc 6M-B from a plugged in IBM Thinkpad. As the program homed and began to make it's first light cut in aluminum the machine surprisingly shutdown and went into the "NOT READY" state. Once this happend I immediately looked over to my laptop and saw that the Windows Star Field screen saver had turned on (I had forgotten to disable it!), but not moving as normal; it was in a static state.
So, I shut everything down, disconnected the computer from the Kitamura and repowered again. When I got to the pendant I saw that the spindle rpm meter had jumped to roughly 900 rpm without the spindle actually being on! Everything else works fine, but now I'm unable to command the spindle to rotate and take the tool out when Z is homed because I believe the machine still thinks the spindle is active.
I have checked the brushes on the spindle motor (they look fine), I can hand turn the spindle without any trouble and the belt drive is in good shape.
I've attempted to command the spindle into different rpms, but it will not turn at all and the rpm meter still says it's moving at roughly 900 rpm.
What would send a signal at power up telling the rpm meter that the spindle is rotating at 900 rpm? Can it be reset?
For any one interested in the fix; here's what I found. The brushless tachogenerator (on my Fanuc 3 spindle motor) had one of 5 wires break loose at it's solder point on the circuit board housed at the very top of the tach. Once I found it and re-soldered it the Mycenter was back in business! Hope this helps someone in the future.