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Mazak SQT-18MS: NC Emergency Stop = Dead??


Feb 6, 2010
South Jersey
When this damn machine runs, it's a dream. When it's down, it makes me question my sanity!

I've posted numerous times on here about my sub-spindle drive woes about 4 years ago and then fast forward to a few months ago:
MAZAK SQT-18MS Run Without Sub-spindle Drive
SQT-18MS Freqrol-SGJ Parameter Change

After all of that, thanks to the wonderful members of this forum, I was able to get my sub-spindle/ live tooling drive operational!
I immediately went to test out the live tooling and it engaged for the first time in years.
It sounded like it was struggling a bit, but turned nonetheless.
Then I ramped it up and.....BOOM.... power module blew AGAIN.
I replaced the module as I have done numerous times in the past, however when I powered the machine up this time, the 40amp control circuit breaker immediately popped.
In my infinite wisdom, I didn't turn the machine off and flicked it back on.....this time, the spindle drive let out the magic smoke.

At this point, I went back to the old thread about bypassing the drive and used the Mitsubishi tech document "How To Eliminate MRS Servos From The Control System".
Starting at the MC617 board, I moved the communication cables and termination plug and success, no alarm.
Then moved on to the X,B servo board and low and behold drive alarm E7 and control alarm 128, Emergency Stop active.
I tested every drive individually with the same result.

I then spent about 3 hours on the phone between Mazak and Mitsubishi trying to solve this.
Kevin from Mazak walked me through the E-Stop ladder diagram and had me test out some relays, with the result being the machine side circuit is actually not active.
This points to the NC or ALL of the drives being the culprit.

Right now, I have a buyer for the machine who is on board with fixing the sub-spindle drive, but I need to be able to show him the main spindle running, the axis moving, and the turret indexing.
Is there anything I could possibly do to check the viability of the other drives, or just get the spindle and axis moving temporarily??

NC Alarm 128, machine side e-stop ruled out, possible issue with every drive or the NC side (confirmed with Mazak and Mits)
Looking to sell, need to move axis and run main spindle
If I can't fix this, machine is either scrap or I'll part it out

Any help would be appreciated greatly!!
Bumping this up.
A new sub-spindle drive has been purchased and installed!
However we've got the same NC Alarm 128 issue.

The physical e-stop circuit checks out.

We've also isolated each servo and spindle drive.
The servo drives each show 128 on the control and E7 (NC Emergency) when isolated.
However the spindle drives ONLY show E7 and not 128 when isolated.

Have spent 4+ hours on the phone between Mazak and Mits to no avail.
Just looking for some guidance on what to possibly check out next.