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IndustryArena Forum > MetalWorking Machines > Okuma > VAC II spindle drive fix notes
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  1. #1
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    VAC II spindle drive fix notes

    as these drives are getting older, are expensive as all get out to repair or replace, thought I'd start a 'notes' thread on issues weve ran across so far...

    just had one with a '1052 VAC input voltage drop' and 14 alarm on the PCB.
    problem was the little tiny Fuji relay in the bottom right corner of the drive had a flaky contact, not energizing the main contactor. lock it out, let it discharge for a while, and you can push the little relay actuator thru the bottom-right side carry handle hole, get a meter in thru the front, got from 10-500 ohms on the center contact(wire 112 feeds the main contactor). my Buddy suggested simply pulling the right side off the drive for access, made it super easy to pull the relay without having to pull all the bussing out from the front.

    twice now weve had them with '16' alarms at boot up, and VAC start failed on the CRT...sometimes cycling the power would clear it...found the 5volt fuse holder beneath the supply was flaky, 5v checked good but was dipping on inrush/bootup- by dumb luck I bumped the fuse and saw flicker...simply cleaned the forks in the fuse holder and scraped the sides of the fuse a little with a exacto blade, problem fixed.

    anyone else with any simple/stupid fixes on this stuff, PLEASE share...I *heard* Okuma wanted 28k for this friggin drive/refuses to supply schematics, and now no longer supports it wants you to update to a newer model...$28,000 for a $2 fuse clip or a $25 relay??? not unless absolutely necessary. these seem to be very very good drives, but they are getting old, suffering from simple failures- at least simple if the OEM would provide adequate drawings... in my opinion if okuma were more open, they would have a lot more fans out there- I'm not one, we need machines to make money, not cost money over 'secret schematics'. I hear Fanuc is getting to be the same way anymore though...

  2. #2

    Great Idea!

    I think it is a great idea what you propose. I know there is a lot of simple fixes for VAC II III Okuma drives, like changing a 25 cent resistor, 10 dollar component, soldering a jumper or even just a simple cleaning in certain areas depending on the fault.

    I know service enginers and techinicians charge big bucks for all this 10 minute work and just a few bucks spent, they have earned it, but we end users with some experience would like to know more and spend less. I do not know much about okuma drives but I have some manual information that I am willing to share in exchange for some knowledge.
    Please PM me if anyone is interested.

    And I repeat, Great idea TC!

  3. #3
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    Great source

    For your older VACS & DRIVES, CNC Repair with engineering excellence since 1988

    Click on:
    •Most Recent DEPOT REBUILDING and EXCHANGE LIST

    Use Ctrl F to find your item

    type in search word

    enter.

    Have used these guys several times. "Quick" great price on repair or exchange with warranty.
    any mechanical or electrical device that transmits or modifies energy to perform or assist in the performance of human tasks

  4. #4
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    BL II-D drive dead?

    had a BL II-D 2 axis servo amp dead last week- no power lights, but 2 fault leds were dimly glowing... found the 10 ohm 5 watt input power resistor was open and the little inline bridge rectifier next to it shorted...
    by just dumb luck fixed it, but hey, it might be a common failure, thought I'd mention in here too.
    a year or so ago, saw another one that acted the same way (dim alarm leds) but I didnt get a chance to check it out...on this one it looked like the bridge simply failed, and overloaded the resistor, replaced with some parts pulled out of a old power supply and back up and running.
    We bought a replacement (now BL IV-D) drive a while back for another machine, $4500 for the new drive... $2 worth of replacement parts and 15 minutes sounded better to me.

  5. #5
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    Quote Originally Posted by OKUMA Tech View Post
    For your older VACS & DRIVES, CNC Repair with engineering excellence since 1988

    Click on:
    •Most Recent DEPOT REBUILDING and EXCHANGE LIST

    Use Ctrl F to find your item

    type in search word

    enter.

    Have used these guys several times. "Quick" great price on repair or exchange with warranty.
    Seems like the first link is not working (well not for me anyway) and the second one leads to a rather obscure eBay book auction item...?

    I would like more info as we have just had a "78 ALARM P" VAC Failed to start 1001FFFF alarm come up on our LB25. It is a VACIII unit and the unit is showing alarm 16 on the actual unit.
    Anyone have any suggestions as to what, if anything I might be able to look for?
    Okuma Australia have quoted us $18750+tax+freight+fitting... bummer!

  6. #6
    Quote Originally Posted by broby View Post
    Seems like the first link is not working (well not for me anyway) and the second one leads to a rather obscure eBay book auction item...?

    I would like more info as we have just had a "78 ALARM P" VAC Failed to start 1001FFFF alarm come up on our LB25. It is a VACIII unit and the unit is showing alarm 16 on the actual unit.
    Anyone have any suggestions as to what, if anything I might be able to look for?
    Okuma Australia have quoted us $18750+tax+freight+fitting... bummer!


    I hope this helps. It is the description of the VAC alarm and the two tables you need for reference 3-5 and 3-3.

    If you like I can email you this pages, just PM me and give me your email address

    jolulank
    Attached Files Attached Files

  7. #7
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    that lack of 5volts error 16 might be that fuseholder I mentioned in the first post- I wouldnt have found it as the 5v was 5.00 with the alarm active, just happened to bump the fuse after one of the intermittent times it booted...

    its kinda hard to check for- apparently inrush was pulling it down, but you cant see when its off...cleaning the little clips in the socket for the little green 5v fuse fixed ours, also corrected a slightly less intermittent bootup in another one- least it hasnt happened since...


    the fibers in OKUMA are actual glass too- be careful not to pull/bend the orange cables any more than necessary- pretty easy to check, just shine a flashlight thru, should be bright on other end...dont think youve got a fiber issue as different alarms, just wanted to mention to be careful around them...one of our guys broke a couple pulling the service in one after a move, another was DOA- the shippers put a bunch of manuals in the cabinet, tugged on one...

  8. #8
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    heloo every body.... how are you?
    could you help me any one know about alarm 17 on VAC III

    Thank you>>>

  9. #9
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    Alarm 17 on a VACIII signals that the power circuit voltage is low (DC voltage in the main circuit is low). The power supply unit could be faulty, the source voltage could be low (should have ~208VAC on R,S,T), make sure the connectors are all seated correctly (CN6, CN7 and CN8), the control board could also be at fault. Basically, there are quite a few things that can cause this. We can repair these drives, and our inspection fee is low. Contact me here: kevin@cnctechnical.com; I need to know what model you have (D6, D11, D22, etc.)

  10. #10
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    If you need the codes and alarms description for VAC or MIP or MIV spindle drives or any servo drives
    on Okuma, send me an email to "contact us" at www.cncopensolutions.com, we are specialized in okuma and help you by sending the proper response.

    Barry

  11. #11
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    Anyone know what alarm 34 means on a VAC111?

    My manual only goes to alarm 32.

    regards, Oz

  12. #12
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    Alarm #34 on a VACIII drive is "Power Supply Voltage Flutter Over", usually caused by a high power source impedance. You can email me here: kevin@cnctechnical.com and I can go through this with you.

  13. #13
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    Had a BDU drive overheat alarm. Turns out it was caused by a gummed up fan on the heat exchanger for the drive that finally stalled and blew a fuse. Okuma wanted around 3K for a new drive. Cleaned the fan and installed new fuse and ran for a few months more before the fan gave out. Found a used fan on ebay for about $40, replaced the fuse again and still going strong a year+ later.

    FYI

    Best regards,

  14. #14
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    I got a 1049 alarm recently. Faulty VACIII unit. The company didn't want to shell out for a new one so I fixed it myself.
    Machine powers up normally and number 02 is shown on the VACIII display (i.e. it's good) but as soon as the spindle is activated it alarms out with alarm 1049.
    VACIII had alarm 11 on it, red LEDS M1 and M2 were flashing and red M3 LED was on. Green LED 8 was on. That means IGBT modules 1, 2 and/or 3 are bad. Alarm 12 means IGBT modules 4, 5 and/or 6 are bad.
    My VACIII is a D22 type. Amazingly all of the fuses were good.
    The repair was to replace one of the IGBT transistor modules. In my case IGBTM1 (the one that's missing in one of the pics)
    Total cost was about $200. Not bad considering a refurbished unit is $6000 and a new unit is $20k.
    I guess I was just lucky it wasn't worse and the top electronics board was still ok. I have knowledge to repair that too, but not the motivation ;-)

    It's very easy to repair the lower part of the older VACII/VACIII drive units.
    The IGBT modules in this D22 unit are Mitsubishi CM400DY1-12E with 3 screw terminal connections and 4 spade terminal connections.
    To check them, with a multimeter set to diode test put red on C2E1 and black on C1 (the 2 outer terminals). then check between C2E1 and E2. Reading should be 0.4 Ohms to 0.8 Ohms. My reading was around 0.43 Ohms.
    Swap the leads around and you should get no reading. If so it's good and test the remaining IGBT modules. At least one should be bad with alarm 11. If bad it'll be shorted (0 Ohms) and G1 E1 and/or E2 G2 will also be shorted. Check the last pic for specifics about the IGBT terminals.

    Replacement IGBTs are available on ebay and many other places. I've spent some time finding cross-referenced parts.

    Compatible modules for IGBTM1 to IGBTM3 (600V 400A dual half bridge with hole centers 93mm x 48mm) are.....
    Mitsubishi CM400DY1-12E
    Infineon (formerly Eupec) FF400R07KE4
    Fuji Electric 2MBI400N-060
    Fairchild Semiconductor FMG2G400US60

    Compatible modules for IGBTM4 to IGBTM6 (600V 300A dual half bridge) are.....
    Mitsubishi CM300DY-12E

    If anyone has encountered different but compatible IGBTs please post the manufacturer and part #


    The hardest part is getting the VAC drive out (it weighs a ton) and pulling it apart, then remembering how to put it all back together without having some spare parts left over ;-)

    Check the pics and VAC II III maintenance manual.....
    Attached Thumbnails Attached Thumbnails VACIII-alarm11.jpg   VACIII-power-board_1.jpg   VACIII-power-board_2.jpg   VACIII-transistor-modules.jpg  

    VACIII-IGBT-module.jpg   VAC_II_III_Maintenance_Manual.pdf  

  15. #15
    Try to contact us "PelicanCNC"
    We can fix any module of Okuma Drives.

  16. #16
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    Bringing this back to the top...I pulled apart my VAC III because I was getting an error code 15, which is an open phase leg. I last powered it up on Friday and all was well. I powered the machine up today and there's the error 15. My input power is low, but it was running fine on it before. Because of this, I pulled the control board off to check the IGBT's(which seem to be fine) and noticed that there are burn marks and several burned components on it. I don't know if these were there before the error or not.

    My question is, what are these things? They seem to be labeled as resistors, but look kinda like caps. Has anyone replaced them and have recommendations on what to get?

    Attachment 202834Click image for larger version. 

Name:	WP_20130929_002.jpg 
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    Thanks!

  17. #17
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    I found out that these are thick film resistors and that they see around 350V. Not sure on power yet, though.

  18. #18
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    Hello everybody .
    I have an alarm on my okuma lb15...it says
    Alarm A - 1068-20
    vac speed deviation too large...
    any ideas?
    thanks

  19. #19
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    Re: VAC II spindle drive fix notes

    I have a 1994 LNC8 with a Vac III (D6) drive. Im getting an alarm 15 on the drive and the M1 and M2 lights are flashing, CPU light is lit , and lights 3&12 are lit green.
    On the control Im getting a 78 alarm-P Vac start spindle 1 1001FFFF.
    Gosiger said their manuals explanation is "open phase".
    .
    I have checked the simple fuses and the breaker for the drive and they are all good.
    Any suggestions would be appreciated
    Thank!

  20. #20
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    Re: VAC II spindle drive fix notes

    that same manual is posted above in post#14.....

    it means one of the 3 phases is not connected so you have a high voltage fault on the lower board of your spindle drive unit.
    you could test the IGBTs and maybe one of them is bad. read my how to test notes in post#14.
    changing the IGBTs does not guarantee a fix.
    if the IGBT blew because of something else then you need to find that something else.
    most of the origins of IGBT failure come from the top board. usually that's the most difficult part because the top board is complicated.

    basically you are screwed and you'll have to buy a new/refurbished VAC III drive from Okuma or some other 3rd party repairer.

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