I sure could use some help with a 1994 vintage Hurco BMC with an Ultimax3. I’m a retired CNC tech trying to help a friend of a friend, but I could write volumes of what I don’t know about Hurcos. To make it even more fun, there are no electrical diagrams available either. Here’s what I’m dealing with...this machine was moved to it’s current home a couple of years ago and was wired up without changing the transformer taps, needless to say that it was expecting 240v input and received 480v instead. I’m told that the power supply as well as the Y axis drive were both fried and subsequently repaired or replaced. The remaining issue that I’m trying to track down is that after power up, the drives will drop out without issuing an alarm (unless the operator tries to move an axis - in which case a “following error” alarm is generated. Sometimes the machine will power up and calibrate the axes and run for a short while (1/2 a day max in two years) or it may drop the drives during or even before axis calibration. Once the drives drop out, a full power cycle is required to restart the machine, and even then, sometimes it will not power up at all.
So far, I’ve checked all the basics, incoming power, transformer voltage, continuity of the contactor legs and reseated all the connectors. I located a contactor that I didn’t have confidence in and had it replaced without positive results. I have tested the 5v, 12v & 24v power supply and adjusted the 12v & 24v down from 13v & 26v respectively. Air pressure & lube level switches all check OK.
A couple things I’m in doubt about are a Tokin noise filter (labeled for 250v) that may have been fried and a blue “Shape Electronics” transformer that has no input/output voltage labels for me to verify. I have not yet removed, inspected and re-seated the various boards in the main processor box. Also, on the left side of the main processor box are a couple of red & green lights. These lights go on & off together when the umbrella ATC is rotating from one position to another, but when the machine has had the drives drop out these lights blink together at random intervals. I thought at first they were some kind of a “blink code” but after reviewing my video of them I found that they blink randomly at anywhere from (1) to (14) second intervals.
This machine is an hour and a half away from me, so I’d kind of like to have a solid plan of what to check and how before I make another trip up there. Right now I’m leaning towards damage on one of the processor boards, perhaps unseating & reseating the boards or hoping to locate a small crack that enlarges with heat? I dunno...any insight you could provide would be most welcome....thanks!

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