Alarm 20 NMI E-Stop Alarm

[stang5197]

On a Mazak 8SP T-2 control, when I powered it up today, it gave an alarm #20 "NMI Emergency Stop" on the position screen.

When I went to the diagnostics screen it showed an alarm #201 NFB (No Fuse Break) Trip alarm as well.

I checked the electrical panels and none of the breakers are tripped but the main board is flashing E7, F1 and F2

Can someone give me some direction on what the problem might be.

Thanks for any help

[Al_The_Man]

Check any NFB's Non Fused Breaker behind the spindle or tool changer motor drive.
The first (bottom) 255 alarm is usually the one that caused it, the rest come up as a result of the first.
Also if the power supply inside the top of the spindle drive can cause it, it should have status LED on.
Check/reset all overloads on contactors.
Al.

[onthebumper]

I agree with Al, after all he is 'The Man'. I would like to add that the alarms you have flashing on the drives you showed are normal. They will always display E7 when the control is in emergency stop but are not the cause of emergency stop in this case.

[stang5197]

Guys thanks for the advice, here is what I have tried so far and still no luck.

I reset the breakers shown in the picture, even thou they were not tripped. I also reset the main 100amp breaker. I rotated the front board from the spindle controller and checked the 3 glass fuses which all were fine.

These were all of the NFB's that I could find, which were located in the main cabinet (pictured).

Al, you mentioned some NFB's behind the tool changer and spindle drive, are the ones pictured the ones you mentioned?

The spindle controller shows R 0 but I can't find where that correlates to anything.

[Al_The_Man]

It depends on what spindle controllers you have, some you have to hinge the front door out to see the NFB etc.
Also make sure you have the cabinet door switch overide on (off?).
It also helps if you have the Mazak electrical prints for the machine.
Al.

[Leelund]

You might also check the status of AVR1 power supply. CB3, a 10 amp single phase breaker, on the BP Panel controls power to it and also there should be a CB5, 3 phase 30 amp breaker, that supplies power to the subspindle inverter if so equipped.

[stang5197]

We found that CB3 10amp breaker was tripped. Once I reset the breaker and restarted the machine all of the alarms went away except for the #20 "NMI Emergency Stop" alarm.

The bigger problem is that the attached board began smoking.

Any idea on a cost for a new board from Mazak/MSU? Also any idea on what caused the board to burn itself up?

[Al_The_Man]

Try phoning Mitsubishi Chicago direct their prices and service is better than Mazak.
They may offer exchange price.
Al.

[stang5197]

Any idea on the root cause of the board failure?

Hate to replace it to have the same problem reoccur, or is this a common thing with the Mitsubishi/Mazak controllers?

[Al_The_Man]

Switching supplies on Mits can fail due to internal component failure, I have found that in the majority of cases replacing the supply cures the problem.
If in doubt, when you phone for a price, ask to be transferred to support and have the board number and system info and see what they say, I have always found them to be very helpfull.
This week may be a bad week as they may not have full staff until the 4th.
Al.

[rhurt]

I had the same problem , found the mar2 relay in the door to be bad chaged it out and everything came on

[bceng]

I have an old mazak QT20 and the alarm NFB 52 came up on the machine. Any ideas where to reset this alarm.

Thanks