[Mike T.]

Hi,

I have a Leadwell MCV 760 XL machining center with a Fanuc 10M control. I have been dealing with a spindle problem where I only have 2 spindle speeds the first is if the programmed speed is at or below 1000 rpm, and the second is at 1001 or higher. I can enter any number as a spindle speed have used 100,000 and the control will not alarm even though the machine only runs to 6,000 rpm.
I have asked the machine side support, and they say it is a fanuc problem,when I ask fanuc, they say it is a machine problem, so I am getting nowhere.

I have replaced the sensor at the top of the spindle motor under the fan. This made the motor run better manually,although it is still a bit rough.

So we started to machine some steel bars with the spindle running at the higher speed and it was working ok, but just a bit too fast. we stopped running to change inserts,when we started again,the machine milled about half way across the part and stopped. the spindle motor was turning but the spindle wasn't, and although the spindle was down in the cut, the tool carousel was turning!
hit E-stop and the machine shut down, released it and started doing the same thing. could not shut the control down either.

The next day, powered up the machine, zero returned all axis and the machine was on but not running. an hour later, the spindle motor was running, tool not spinning, the carousel was turning, and the coolant pump was running and again, the control could not be powered down.

This machine is an important part of our operation and needs to be fixed. Replacing it at this time isn't an option. Any help would be greatly appreciated.

[tc429]

if they use the same relay board in the back as the zero equipped machines, thats likely your current problem. we had a dozen or more of the zero equippped mcv760s and all of them had boards burn up- a couple literally. I 'fixed' a few by taking a dremel and hacking out the charcoal areas and bridging traces, but had other machines to compare to/follow traces. look with a flashlight between the little relay bases for signs of a small fire- they ran 200/100/24 volt traces under the sockets and the least bit of moisture gets under them, they light up. leadwell aparently had major isses new, as all ours had bigger relays bugged in to a dangling cable, running more decent sized relays in the bottom of the cabinet. great machines, pathetic wiring. those boards and the operator panel toggle switches shorting out(facing up/unsealed) were constant issues. we eventually threw the relay boards out and redid with normal discrete relays, cheap, simple, reliable- but a bit of work as all the cables had to go- we even tossed the rear cabinets for better hoffman enclosures about half size.

as for the spindle rpm thing, i dont have a 10/11/12 connection book handy- if you have one, look up the spindle 12 bit output address, think its G24/G25 but been a long time... anyway at maximum commanded rpm, and 100% override, those two addresses should show 11111111 and 00001111. if not, your parameters/pmc are affecting it- if they are all 1s, program exactly half of maximum rpm, the highest bit should drop out (11111111 / 00000111) if that works, but your rpm dont change, then most likely i would expect the little 455 op amp near the spindle LSI is bad. they dont fail often, but they do...(again I am assuming the 10 has similar structure to the zero- been a long time since working on a 10). changing the op amps isnt horrible- but i wouldnt recommend learning to desolder on a board that expensive...

hopefully your binary 12 bit output is just not working right, check the above and post back, sure someone can chime in.

hopefully *if* your back relay board fried you might just be able to dig out the shorted areas carefully and bridge any trace holes- watch the wire numbers though- they mount that flimsy board on a hinge, but the wiring prevents swinging it out to look at the back- ive always had to unwire and remove, sometimes the wire numbers dont match the terminal numbers.
leadwell sells those boards still i believe- a few 'ifs': if you have have a fried board and if you have time and if want to try to fix it yourself- try to get some good clear pics of the whole board showing the holes, and a close up of any burnt areas- maybe i can find one to get a same view of showing traces... we're out till monday though- but again, our leadwells all had zeroes, not tens (think they had the same board- i saw one once). good luck