[SSracks]

We were not able to figure it out ourselves, we could not find anyone to supply parts so we sent it out and had it repaired. Cost was $2600 US but it came with an 18 month warranty.
Okuma does not provide support anymore on these drives, they will only sell you an upgraded replacement which is very expensive.

[CNCRebuilder]

good thread guys, I'm going to follow and try to chime in here as well.

[kennybennett]

Any chance anyone here knows what an alarm 11 on the VACIII Drive Unit means? It comes with a short-circuit warning on the Okuma lathe op panel. I have already checked that my spindle motor is not bad. I can clear the alarm by turning the machine off and back on again, jog around the axes and jog the spindle, but when I go to put it in sequence restart to restart our part program, it alarms out with alarm 11 on the Drive unit. Any help would be apprieciated.

[motorway]

hi, i have a VAC 3 D11, having some issues & not sure if they are related, The 2 fuses at the bottom of the drive unit are blowing when the power is turned on, the manual has zero info on what these do.
Anybody have info about these fuses?
And im also getting alarm 06 watchdog error on the drive.
thanks

[mujkance]

Hello kenny

I think alarm 11 can be caused by faulty IGBT modul. Do you know how to check it?

If you don't know, follow this. You don't need to pull out VACIII drive. Disconnect motor cables from VACIII drive. Just do measuring between DC link and AC outputs for motor. Use diode test on multimeter. When you put red probe (+) on (-) pole of DC link and black probe (-) on AC output for motor, you should read value about 0.4. Do it for all three motor outputs. Than put red probe on (+) pole and do measuring for all three outputs. You should read nothing on multimeter.
Than swap out probe, put black probe on (+) pole of DC link and red probe on AC outputs for motor. Reading should be about 0.4 again. Then put black probe on (-) pole of DC link and repeat you measuring. It should show nothing.

If you have short circuit during the test (multimeter gives you a beep sound), than you have a problem with IGBT modul. For example, if you have a beep sound when you measure second output for motor, the problem should be with second IGBT on that side.

I hope this was helpfull...

Best regards,
Samir

[doctorcnc]

RE: hi, i have a VAC 3 D11, having some issues & not sure if they are related, The 2 fuses at the bottom of the drive unit are blowing when the power is turned on, the manual has zero info on what these do.
Anybody have info about these fuses?
And im also getting alarm 06 watchdog error on the drive.
thanks

Hi: Better to start a new thread on Okuma VAC3 D11 spindle drive. Anyway, the two 1/4" fuses are for the spindle motor fan and drive control power. The two common reasons the fuses blow are gunked up spindle motor fan or the varistors on the circuit board (green discs about 3/4" in diameter near the fuses, explode. If the varistors exploded, the drive is toast, as the arc flash damages Okuma un-obtainium parts on the top board. If the fan is the problem, fix the fan. Alarm 06 on a VAC3 D11 is 'Resolver error', not watchdog. Watchdog alarm is 26. If you are getting a 26 alarm, then probably the varistors exploded. Also search this forum for: http://www.cnczone.com/forums/okuma/...ml#post1718506 .
You are welcome to contact me at 408-331-1970 Jim, if you have further questions. We also rebuild and exchange rebuilt Okuma VAC3 D11 drives.

[BadTad]

Having Problems with my VAC III D11
Originally Alarm 15 - as I understand this would have been an 'open phase' perhaps pointing to the bottom board.

M1 and M2 are flashing red. 3 and 12 lit up.

Now however, it will not light up at all. Not reading power on the board, but there power on the connecting PCB (from bottom to top)

I don't see any obvious failures on the board, and all fuses checked OK.

Okuma wants 9400$ for new unit. Found a rebuilt with 12 month warranty for 2700$, still over my budget right now... hoping for an easy fix..

Incoming power is 219-220v measured from RST

Attachment 324042

[BadTad]

Having Problems with my VAC III D11
Originally Alarm 15 - as I understand this would have been an 'open phase' perhaps pointing to the bottom board.

M1 and M2 are flashing red. 3 and 12 lit up.

Now however, it will not light up at all. Not reading power on the board, but there power on the connecting PCB (from bottom to top)

I don't see any obvious failures on the board, and all fuses checked OK.

Okuma wants 9400$ for new unit. Found a rebuilt with 12 month warranty for 2700$, still over my budget right now... hoping for an easy fix..

Incoming power is 219-220v measured from RST

Attachment 324042

Also, I just checked the components on the bottom board and they are fine. Getting 300v to top board between pin 3 and 4 on CN 8.

However my 15v is reading 22v, and my 5v is reading 3.75..

[doctorcnc]

Generally, rebuilding the top board will fix 15 alarm problems, assuming you can measure 3 phase 208 on TOP of the main circuit breaker and all the fuses are OK. Rebuilding the top board also fixes power supply problems, assuming the 12 clear plastic fuses on the drive board left measure OK. Contact me at cncrepair.com for a quote. If any of the clear plastic fuses are open, I recommend a swap for a rebuilt drive. We usually have these in stock. 1 year warranty.

[cncts11]

If you want to contact me to discuss your drive issue, you can reach me at 585.742.1490, ask for Kevin.

[boyder]

I like the Idea of this execpt I always have more questions then answers sometimes !
I have a LB-25 lathe we just moved machine to a differt bay same building and when I turned it on it booted up everything works until you try to turn on spindle . Get alarm 110 sdu 1 .I looked at drive itself and the m2 red led light is on steady once it alarms .The machine has transformer and the power out of transformer is 215 volts ( not sure if is to high . Has any had this issue ?
Thanks Boyd

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...

[semiherol]

Hi, were you able to solve this alarm issue?
can you help us?

1068-20 ALARM -A vac speed deviation too large SPDL

[COMESI]

Hi Kevin:
I get this alarm too.
Can you help me about this alarm?

[JESUS21]

my okuma have same problems but only 800rpm

[Biksus]

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.....

Thank you so much, fordav11 for the info. You are awesome. I was able to fix the drive. I used FF400R07KE4 to replace CM400DY1-12E. FF400R07KE4 has longer distanse between power terminals though. I had to file contacts on the board to fit it.

I wanted to add something to this. In my case, IGBT was not shorted but burnt in the open state. To test this you need to do this:
1) Set multimeter to diode test mode.
2) Set a positive probe of multimeter to B1/G1 and negative to E1. C2E1 and C1 should be opened in both directions (C2E1 to C1 and C1 to C2E1)
3) Set a positive probe of multimeter to E1 and negative to B1/G1. C1 to C2E1 should be closed (C2E1 to C1 is still opened through the back diode)
The same thing for the other transistor:
4) Set a positive probe of multimeter to B2/G2 and negative to E2. C2E1 and E2 should be opened in both directions (C2E1 to E2 and E2 to C2E1)
5) Set a positive probe of multimeter to E2 and negative to B2/G2. C2E1 to E2 should be closed (E2 to C2E1 is still opened through the back diode)

Hopefully, it will help somebody.