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Mazak FJV-250 Mazatrol 640M - Alarm 341 - ATC rotation malfunction

Aug 8, 2022
Hi everyone,

This is my first post on here so hopefully I've provided the right information. I recently purchased a 1999 Mazak FJV-250 with Mazatrol 640M control. After getting it hooked up and moving around and replacing the battery on the magazine drive I tried a few tool changes. They worked fine at 6% rapid but when I increased it I got error 341 ATC rotation malfunction. Unfortunately the manuals that came with the machine are missing all errors between 199 and 400, so I have no documentation about this error. Furthermore, Mazak is taking quite some time to set up my service account and won't help me until they do so I'm on my own at the moment.

I've been researching similar issues and tried a couple things. So far I've manually jogged the spindle out of the tool change area so the door could close, removed the cover on the motor that moves the ATC arm and manually turned it both ways with the machine in estop. It moves to both ends of its cycle with no issue. With the hydraulics on I manually triggered the solenoids to move the shifter arm back into position over the magazine (when I got the error it was stuck forward into the rotating arm). On the control I've went into the maintenance mode and pressed a bunch of buttons like ATC 180CW and 180CCW but that does nothing. I can get the tool magazine to spin and home but the arms won't move. Now I also can't home or move the X or Z axes because of internal interlock errors, but Y moves fine.

This is my first time using a Mazak control so I'm not sure if it's an easy fix that my lack of experience can't solve, or something like a sensor not indicating when the rotating arm is in the correct position.

I can take pictures of the current state tomorrow if that would help. Thanks in advance for any insight on the matter.



Dec 17, 2012
I can only say Interlock problems come down to something not being EXACTLY where it should be. Axis does not know where it is, does not want to crash. Sometimes so freekin close, but close is not good enough. Sometimes not even telling you the issue.
And my first Fusion machines would give me errors that were not in the manuals and I would have to call Mazak. Replacing MRJ2 (magazine) battery requires a reset of some type and a power off, back on to clear.
I also have another 640M that will throw a SENSOR POSITION HALF error or something like that. 48 tool magazine. Machine will open mag door and stop dead with that error. RESET, manually jog magazine one way or the other, restart the program where it stopped.
I only had to do an ATC repair procedure once on that machine, PITA. Nothing was broke but I made an error judgement and tried to put a very long spade drill into the magazine that I loaded into the spindle from the front. All looked well until the spindle lowered and the arm pulled down and tried to get through to door with the tool. Tool just hit the lower sill when I slammed the estop (cut my finger on it too). Tool was then partially crooked in the swing arm. Do not remember how I got the tool free but I did. After hours weekend call and got it back online in a few hours.