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Hitachi Seiki HT20 Motor alarm

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Jun 8, 2018
So we have a Hitachi Seiki HT20 Lathe with a Fanuc 3TF control. Yaskawa Spindle Drive. Running fine and this morning I came In and fired It up. Put It In warmup and walked away. Came back and I have the Red Motor LED on the control Lit. Machine In the Not ready state. Nothing tripped. It has two DC power supplies In the back cabinet. One is a 12V the other is a 5V. Good AC power going In. Neither produce 5V or 12V. Seems odd to me they would both die at the same time? Could something else have wiped them out? Any Ideas at what else to look at? Or would you just replace the supplies and see what happens?

Pulled all the outputs to make sure something else wasn't pulling these down. Still good 115VAC Incoming. Nothing on the DC outputs.
 
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The issue is most likely with the 'Micron' controller that runs the m-codes and I/O for the Fanuc control.
Well, the DC power supplies mentioned above feed the Micon-8 CPU Board. So are you saying the board probably took out the power supplies?
 
Micon 8 ( both versions ) had external and internal power supplies.
The CODA board has 2 internal regulators. One of them is a all-in-one voltage converter module.
The test points are easy to find.

1679332278394.png
 
Yes Sir, I get that and I already have a set ordered. It just seemed odd to me that they would both fail at the same time. The 24V supplies are good. The Micon-8 shows LED1 Lit Red. and LED4 Lit green. LED1 is a battery low alarm. LED4 strangely enough is ON/POWER SOURCE +5V. I can't quite figure that out. I get no 5v or 12v readings.
 

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  • HitachiSeiki_Manuals_447-1.pdf
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I have probed those. Whether I probe there or the test pins or directly at the power supplies. I might get 3V or -3V then It dissipates to nothing.
 
I will have the new ones tomorrow. I will report back when I get them Installed.

Thank you for your Time, I appreciate your help.
 
Ok,
I pulled out my book last night. This is all I got on the micon 8. It was a little before my time with hitachi.

First thing =>> Change your batteries with the control on.
It is a bunch of AA batteries in a little plastic holder. They might be hanging loose behind the CPU board or around the card frame.

If you have lost the parameters from dead batteries, I have included the 'default' parameters for the NR series and NF series lathes.
 

Attachments

  • micon 8.pdf
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  • micon para & alarms.pdf
    512.3 KB · Views: 9
Ok,
I pulled out my book last night. This is all I got on the micon 8. It was a little before my time with hitachi.

First thing =>> Change your batteries with the control on.
It is a bunch of AA batteries in a little plastic holder. They might be hanging loose behind the CPU board or around the card frame.

If you have lost the parameters from dead batteries, I have included the 'default' parameters for the NR series and NF series lathes.
I just read this posting today 4-18-2023, Question to ask is that I have is have you checked the spindle motor itself, for dirty fan motor and build up around motor as there is a temperature probe built into the motor that can produce alarm message if motor over heats.

Ken
 
Hello Ken,

The Spindle motor on this machine was rebuilt not long ago. So that Is fine. Problem ended up being a bad hydraulic pump motor. The motor was bad and the coupling between the pump and motor was so wore after 40 years of service that we just replaced them both. Machine Is making parts again.
 
Ok,
I pulled out my book last night. This is all I got on the micon 8. It was a little before my time with hitachi.

First thing =>> Change your batteries with the control on.
It is a bunch of AA batteries in a little plastic holder. They might be hanging loose behind the CPU board or around the card frame.

If you have lost the parameters from dead batteries, I have included the 'default' parameters for the NR series and NF series lathes.
Amazingly enough we didn't loose the parameters on the Micon-8. Good news Is I have all the original manuals and settings If that we're to happen. Truth be told when I looked at those batteries they were so old they were leaking. I couldn't believe they were still holding enough voltage to keep the Micon-8 alive!!!
 








 
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