Kitamura MyCenter 0 w/ Fanuc O-Mate - Losing spindle operation in strange way

[SteveCNC1969]

Hello all.
I have a Kit MyCenter 0, vintage 1992, with a Fanuc O-Mate series C controller. Here is the issue. The machine will work perfectly but all of a sudden the spindle will stop operating (turning). The strange part is that the spindle motor is still energized, verified by measuring voltage at spindle power leads and when the spindle is MDI commanded on it doesn't spin freely by hand. I've spoken to Kit and Fanuc and they both agree that the motor is being commanded on and it being energized but the spindle drive is waiting for a speed command and it doesn't see one so it just hangs in limbo.
I've checked the LED readout on the spindle board and it stays at zero during a MDI spindle on command, but if I manually spin the spindle (I put a half inch stock in a tool holder and spun the spindle manually with a hand drill) and the LED readout moves up and down. So I know the spindle motor is giving the correct current speed information to the spindle drive. I've also taken the spindle motor out and hot wired it to a different machine and it works perfectly.
I've also swapped out the I/O board and memory board and I get the same problem even with the new boards installed. Keeping in mind that I have to use the old memory chips on the new memory board. I even sent the spindle drive out for testing and it came back as working perfectly. I also check the parameters on the spindle drive and they match up perfectly with the factory specs.
Here is the kicker. Let's say the spindle is not working as the condition stated above. If I reset the controller and reload the parameters it will work just fine. I know what you are thinking, that a parameter has been changed and I am resetting them to factory and that's the problem. Unfortunately not. If the spindle is in the not working state I can download the existing parameters and diagnostics (as the machine sits not working), re-upload those same parameters and diagnostics and the darn thing will work! It will work for a minute, day, week, month, it's all random. I've called Kit, Fanuc, and a bunch of techs and no one has any idea what is going on. I've even check every param and diag in the non working state and they all match perfectly. I've also check every single wire/relay/switch/anything and everything I it's all in good shape.
I'm the second owner and the machine is in really good 'unmolested' condtion.
I'm at a loss here and even techs that have come to diagnose the machine say that I've done every test they would have done and they have no idea what is going on, "and that will be 500 dollars thank you".
I'm losing money and time and sleep trying to figure this one out. I'm short of selling a machine I love. Any suggestions anyone?????
Thanks, Steve

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[jbaz]

It sounds like you've done just about everything to test it and it sounds like a gremlin with the memory/chips. I know you've had it tested, but it is hard to explain why it will work fine the moment it is restored with identical data. It really seems like something is getting corrupted.

[motionman]

Id like to learn more about this issue, including location because I have a lot of good contacts at both Kitamura, and Fanuc Please email me at tacmubuntu@gmail.com

[shas595]

Normally, the RPM of a spindle, at least on some machines I have worked on, it translated via a small amount of DC voltage. So say, .5VDC would be 250RPM, 1.0V would be 500RPM, etc. I had a bad wire that was degrading the DC voltage being input into the drive, it was a Yaskawa CIMR-MTIII series spindle, and I was getting fluctuation in the RPM. Another issue I had with spindle speed, and this one really had me pulling my hair out, was the Rapid Override rotarty switch. I had one that was loose, so every little vibration caused the spindle to flucutate. I replaced every part, only to find the connector was half off and every time the operator leaned on the machine it would jump around. Just some ideas to consider
John

[SteveCNC1969]

Thank you for your suggestions John. I was able to further diagnose my problem (although still not solve it). I removed the LSI chip from the main board, started the machine and commanded the spindle on and the spindle works. Seems with the LSI chip removed the spindle defaults to 2000 rpm no matter what the spindle speed command entered. This shows that all the wiring, encoders and other components are working fine. If the spindle didn't work with the LSI chip removed then it could be a hardware problem for sure. With the chip removed and the spindle working it's an indication that the rest of the hardware is functioning properly. With the LSI chip installed I am not getting the variable voltage signal to pin DA2 on the spindle drive. This variable voltage is what tells the spindle drive what speed to turn the spindle. Seems the spindle IS getting the command to turn the spindle on which is why it's getting energized but the spindle drive isn't getting the spindle speed command via variable voltage signal to pin DA2 on the drive. I did purchase a new LSI chip but that still didn't work.
In the past I would reupload the parameters and diagnostics to get the spindle working again but now even that doesn't work. I have a service ticket in with Fanuc and hopefully they can figure out something, if not then it's a Kitamura issue.
FYI: The LSI chip is the long 42 pin purplish looking color chip that is on the main board right next to the power supply, it's numbered MB87103 on my machine but the LSI chip numbers can vary. LSI stands for "Large ScaIe Integrated". This chip was created in 1979 and is able to perform multiple functions that previously needed multiple components to do the same. LSI chips can be found also in servo axis controls.
I'm am starting to believe the problem is with the Kitamura program chips. I've contacted Kitamura and requested information about replacement program chips but they still haven't gotten back to me.
Still searching for a solution, still no machine running

[SteveCNC1969]

New update.

I purchased a new (used) main board off Ebay (that supposedly is working) and replaced it last week. The spindle now turns but ONLY 4 rpm. No matter what speed I command I only get 4 rpm. If i remove the LSI chip I still get a default of around 2K rpm but with the LSI installed the spindle will only go as fast as 4 rpm. This is a little better than before where I wasn't getting any spindle speed. I contacted Kitamura and Fanuc and they said nothing special needs to be done when replacing the main board. Just in case I re-installed the machine memory and re-initialized the spindle drive and checked it's parameters, all were fine.
In checking the diagnostics #53 bits 2 and 3 change respectively when commanding an m3 or m4 rotation command. Strangely though an M19 orientation command does not work at all, even the diagnostic #53 bit 0 doesn't change when commanding an orientation command.
I keep chipping away and I'm getting somewhere (I hope) but I'm still lost and without a working machine.

[raceproven]

Hi. I have the same problem... where you able to figure out your issue? Your help greatly appreciated. Kitamura Mycenter 1.

[SteveCNC1969]

Just sent you a PM
I have another main board coming in tomorrow, will post results when I know ....................

[SteveCNC1969]

Here's the latest update on my FIXED Kitamura Mycenter 0 machining center. On replacing multiple boards/chips reinstalling parameters/diagnostics a million times, countless hours on the phone with Kitamura and Fanuc and outside tech support, multiple visits from multiple machine repair 'experts', I've finally figured out what had happened.

I'm almost embarrased to tell you what I found was causing my problem. My only saving grace is that no one else, including the experts and the people that made the machine/controls, also couldn't find the problem.

Yesterday I ended up replacing the main (mother) board at the suggestion of Fanuc. Unfortunately this didn't solve my problem. Standing there scratching my head I aimlessly paged through the ladder diagrams, again, hoping to see something .... just something that I might have missed. Now I'm no expert for machine repair, I'm just learing as I go forward. I DIDN'T know how to read a ladder diagram, but like everything I've done so far I've 'self taught' myself.

In going through the ladder looking for misc spindle control commands I happened across the tool clamp ladder diagram...... hmmmm. I looked further into the tool clamp indicators as I did remember reading somewhere in the owners manual that the spindle shouldn't be operated with the spindle in the 'tool unclamped' position. The diagnostic number for tool clamp is 8.0 (first digit from the right) and tool unclamp is 8.1 (second digit reading from the right to left). When the tool is clamped 8.0 goes from 0 to 1, when the tool is unclamped 8.1 goes from 0 to 1. Sooooo, it seems 8.0 was NOT going to 1 even though the tool WAS in the clamped position.

WTF! Flash back to an earlier time when I had an issue with the tool pot not coming forward to change a tool. It seems there are two things you need to remember about these machines, there is a mechanical action and a separate electronic indication of that mechanical action. In other words, the machine may actually do something mechanical ( like tool pot forward or tool clamp ) BUT if the electronic indicating device such as a sensor switch isn't activated the machine doesn't know that the mechanical action has actually taken place or has completed. (my tool pot wouldn't go forward because the carousel door sensor switch was misadjusted and not indicating the door was open when it actually was)

Seems that all my trouble was a misadjusted tool clamp switch at the top of the spindle which would indicate that the spindle/tool was actually clamped. The machine wouldn't turn on the spindle to protect itself, SMART!

All it took was a simple twist of a small disc mounted on the top of the spindle shaft to contact the (upper) tool clamp switch and poof the spindle started turning immediately. Funny thing is I had no alarm, I guess the older machines can only be so smart. I did however unplug the clamp/unclamp switches and I got a 2003 ATC Tool Potition alarm (which is a Kit 03 alarm) when pressing the unclamp button (no alarm when pressing the clamp button). Weird as if I ever got this alarm I would be examining the ATC portion of the machine and not the spindle clamp sensors.

Also ( I just happened to notice ) when pressing the clamp button diagnostic 2.4 turns to 1 and when pressing unclamp 2.5 turns to 1 (ONLY when pressing the button and holding it down). This is a good way to see if your machine/control is sending clamp/unclamp signals from your control panel, helpful IF you have a clamping/unclamping problem.

So it was the tool clamp sensor switch all the time, I'm finally back up and running!