Yaskawa AC Spindle Drive problems...blown?

[nlh]

Hi folks,

We have a Takamatsu EM-2 cnc lathe here at our shop. Some of you reading this post will probably remember my post from other sections asking about this machine. We obtained the machine on a trade and have little into it. It was previously owned by a trade school and has seen less than 52 hours of total automatic operation time. The control is a Yansac 2000G and the machine is a 1980 model year. We moved the machine into place and wired it up only to find that a few breakers were tripped. These were reset and the power on prodedure(e-stop off, power on, wait 5 sec, power on again) produced a code 28. Found a couple more breakers I had missed and the machine came into "Ready". We attempted to jog the axis which moved fine, except for some bent sheet metal(binding). Then attempted to jog the spindle. Spindle emitted a rough growling noise and jumped erractily back and forth then threw the machine into alarm before we could get it stopped. After fiddling around in the back with the breakers the machine came back on ready. We attempted the spindle again with one finger on the "forward" key and the other on the "stop" key. Machine remained on ready longer but spindle still jumped and eventually(before I could press stop) produced another alarm. Machine was shutdown and brought back up but with a persistant alarm 28. After much digging I found 2 fuses blown on the spindle drive which to my surpises was a Yaskawa Servopack CPCR-QC758SC-4KB AC Inverter drive. I was expecting a dc spindle drive and spindle motor with possibly a stuck brush from sitting. Spindle motor is silky smooth when turning over by hand. Both fuses were replaced with the same result. power on, wait 5 sec, power on again and immediately the fuses blow. I found the maintence manual on Yaskawa's website and followed the block diagnosing diagrams. At first it led me to believe that one of the Darlington transistors was bad but further investigation caused the machine to trip the main breaker. I am very worried that there is some serious damage to this drive and I can just about imagine what Yaskawa will charge for a repair or replacement. According to what I read in the manual the most likely cause of an jumping erratic spindle would be a resolver issue however their appears to be no broken or shorted wires. One thing I should point out is that when we got the machine back to the shop, the gaurd that wrapps around the spindle motor was bent. We took this off to repair it only to find the amphenol connector that plugs into the back of the motor(either a resolver or tach, really not sure) was broken and bent most likely due to a forklift accident. The broken piece was the chassis mount and it was replaced with a new outer shell. This was done before the machine was wired up so I don't have any before/after information. Has anybody out there had any experiences with these AC inverter spindle drives? Anything you guys could give me for hints or places to look for this problem would be wonderful. I would hate to have to junk such a lower hour machine due to this, but we have a very small budget to work from. Is it possible that we could use a newer Yaskawa VFD in place of this one? The current unit has about 4 or 5 layers, 2 boards on top, a layer of transistors and diodes, then some very large resistors and a large capacitor. Sometime in the future when time permits I was going to removed the unit from the machine and visually inspect the components for something obviously wrong, however most of the IC's have had thier marking removed. If anyone has any questions on the above timeline please let me know and I'll fill in the gaps as best as possible. This has been going off and on now(when time permits) for the past week. ANY help is more than appreciated! Let me know....

Thank you