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Yasnac LX3 - Z Axis Alarms


Nov 10, 2012
Kia KT-15 Lathe - Yasnac LX3 control

I'm posting this here as there isn't a machine specific forum for my lathe or its control.

Went out and fired the machine this morning and immediately had 3 alarms all Z Axis Servo Amp related.


332 - FUSE (Z)


Servo pack alarm - 2 ( circuit open/breaker open )

The 280 alarm is normal at start up so it's irrelevant but was there.

So I saw the fuse alarm and immediately though it was a breaker/fuse on the Z Axis Servo Amp. Checked and it had a breaker that wasn't tripped. Since the machine was running fine the last time I found it a bit hard to believe it was a bad servo amp. Proceeded to check incoming voltage, connector connections, power supply and so on, etc, etc... Frustrated at this point I pulled the amp out to have a closer look at things. Pulled the boards out very carefully looking for anything obvious. Checked resistors, capacitors, diodes, connectors and what I could check with a multimeter. Couldn't find anything that seemed bad or wrong. Put the drive back together and reinstalled it in the machine. Fired it up and all was good for about 5 minutes. Then same exact alarms again. Immediately scratched my head and checked the breaker in the amp and it wasn't tripped. Again I started checking things again. Pulled the drive again. Checked everything again. Reinstalled it. Same alarms.


Started looking for a new/good used drive. Jaw dropped. Looks like I'm getting it repaired. All this time I'm thinking none of this makes any sense. Worked fine all week with no issue. In my experience servo drives don't go bad like that. Decided to check the connections at the servo itself. Pulled them and they were a little dirty but I've definitely seen worse. Cleaned them with contact cleaner, put them back together, fired up the machine, alarms gone. Proceeded to run 60pcs with no issue.

I'm basically posting this for anyone who may have the same machine/control system who may run into this problem. A new/rebuilt drive is $1500+. The only thing I can figure is there was a bad connection at the encoder connection and wasn't getting a signal back to the drive. Seems wierd it would throw those alarms though and I'm still somewhat skeptical. We will see what happens going forward. Hope this helps someone out there as I spent the better part of 6hrs trying to figure it out.

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