Mori Seiki MV-Jr Servo packs not starting up

My MV-Jr worked last week... but yesterday and today it won't start up. The control comes on, but the servo packs won't fire up. I get errors for all 3: 391, 392, 393 SERVO ALARM. My control is a Yasnac MX3. If there's a good repair guy on the east coast, I'd be happy to consider paying for a call. Otherwise, if you don't mind helping out, I may be able to do this myself.

I don't know much myself but do you know what those alarms mean? Have you downloaded all the info on your control and servos from Yaskawa? Here is the manual and the other info should be easy to find MX3 Operator's Manual - Yaskawa

Thank you, David, for responding to my plea for help! The operators manual doesn't offer any help on these 3 error codes. It simply restates what's on my screen "SERVOPACK ERROR". I'm thinking its got to be something common to all 3 servopacks; power supply, safety lockout, etc. I don't think all 3 servopacks would go bad at the same time. Mori Seiki will usually talk to me on the phone, but they will probably deflect this one off to Yaskawa, since its their control. I don't know anybody at Yaskawa, and I haven't received much help from them in the past.

gcriniti said:

Thank you, David, for responding to my plea for help! The operators manual doesn't offer any help on these 3 error codes. It simply restates what's on my screen "SERVOPACK ERROR". I'm thinking its got to be something common to all 3 servopacks; power supply, safety lockout, etc. I don't think all 3 servopacks would go bad at the same time. Mori Seiki will usually talk to me on the phone, but they will probably deflect this one off to Yaskawa, since its their control. I don't know anybody at Yaskawa, and I haven't received much help from them in the past.

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I found the info on my servo drives and spindle drives for both my J50 and J300 controlled mills using the search function on Yaskawa's web site, the manual link was just so you knew where to look. While your stuff is a bit older the technical information may be there.

The problem with calling Yaskawa about problems with your machine is they have no clue how their stuff was integrated and what what options were used. This tech help is really on the MTB and not Yaskawa.

As I said earlier I don't know much, but since the problem involves all 3 drives then I don't think it is the drives. Knowing what the error codes mean would be the start. Another item that is easy to check off the list is do you have any alarms on your low voltage power supply? 12v is for the control, 24v is for sensors/limit switches.

I've been studying the ladder diagrams and trying to match them up with the actual components on the machine. I'm not good at this. Your advice is sound. I quickly checked the power supply. The green lights come on for "source" and "power on" as I think they should. The red lights for 5V, +/-12V, and +24V do not come on. Since they are red, I don't know if that's good or bad. I'll put a meter on the lines and see when I have more time. That's all the time I have for today. Thanks again!

gcriniti said:

I've been studying the ladder diagrams and trying to match them up with the actual components on the machine. I'm not good at this. Your advice is sound. I quickly checked the power supply. The green lights come on for "source" and "power on" as I think they should. The red lights for 5V, +/-12V, and +24V do not come on. Since they are red, I don't know if that's good or bad. I'll put a meter on the lines and see when I have more time. That's all the time I have for today. Thanks again!

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What your looking for is an alarm on the power supply, which when it happens probably tells you there is a short. Low hanging fruit that is worth checking.

A common cause of all drives being alarmed is an axis on a hard overtravel limit switch or an e- stop button being pressed. Have you checked those things?

I have a pallet changer attached to my mill and it has an e-stop. It's my primary suspect right now. The pallet changer has been moved, and I'm concerned that wiring may not be plugged in correctly, or making good connection.

I've verified the pallet changer is plugged in correctly. I'm still not comfortable that the estop is working correctly, though. Can you guys tell me how the estop works? From my ladder diagrams, I see the estop is normally closed and connecting P24 to N24. Should I get a +24v on this line?