[WGJ]

After letting my 1987 LB-15 sit idle for a week or so, we needed to start it for a run. It boots up like normal and the y axis moves fine...but when you try to jog the z axis an alarm pops up.

100-4 Alarm-A DIF
over z-axis 38B98

We looked at the servo and screw for the Z. Powered down, you can move the screw by hand easily both ways. When you try to jog, it does not move the servo at all. I looked at the drive card. Before you put the machine into fault (alarm) mode, the x axis has a green light on but the z does not. When it goes into fault, there is a yellow light on y axis (card) and again no lights on the z axis.

Any thoughts?

[Riddersholm]

In your Axis data page what is the RDIF/RCON and RAPA values on the Z Axis?

[WGJ]

In Non-Faulted mode RDIF=0 RPAP=325.8477 RCON=325.8477 RLOAD=-163
In Faulted mode RDIF=-.3347 RAPA=325.8477 RCON=325.3928 RLOAD=0

[Riddersholm]

My guess is either and encoder fault or a Axis driver card. If the driver card and SVC card is the same on both Axis 50A/50A for example you Can Try switching then and if the erroer moves to the X Axis you found the fault.

[underthetire]

Check the breaker on the drive, should be next to the power terminals under the top board. Drive should have a green light on, since it has no power the axis simply isn't moving though commanded to do so.

[CarlosM]

Hi, does the servo card has no lights on it after switch on power? , if so 100% sure that problem is on card, you should change it but be sure to check if power transistors are ok cause if not, they can burn a new drive card again.


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[CarlosM]

Hi

Don't change the cards between drives without testing before if power unit is ok ( a failure in a power transistor can burn again a new drive card). If no lights are ON 100% the problem is on the card, but please check power transistors and 3phase rectifier ( they are located under the drive card)

If you want to contact me for further explanations please contact me at [email protected]


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[WGJ]

I tried the breaker...and the reset on the contact relay. They are fine. I ended up swapping leads and top boards to see if the power side (bottom) was bad. Once I swapped these, the upper board was z and the bottom was x (reversed). I had the same symptoms. The x top card lit up plugged into the z bottom side and the z top card was still dark. I think this proves that I have power to the Z top card and not through it.
The x and z top cards are the same part number, but the dip switches are in different position. I believe this top card is my problem, and assume that I can purchase one, set the dip switches like my original unit, and plug/play. Is this reasonable?

[Riddersholm]

This is it. But these old cards are not available "New", you will have to upgrade to BL-4 card. Or buy a used

If you buy a new BL-4 the dips switch will be different

[underthetire]

And the new drive units cost as much as the machines. As much as I like Okumas, i can't believe the poor support for older controls.

[Riddersholm]

In my region approximately 4500£

[underthetire]

Yep, about 7K US, however i think they charge closer to 8K here. If it was Fanuc, you could get an exchange unit for ~$2200.

[fordav11]

we have had the same issues about getting replacement units for servo/spindle drives.
Okumas excuse is they can no longer get parts to repair the drives from the original manufacturer. the cause of the fault is almost always on the top board.
The excuse is very weak since it is still possible to buy parts from other places and I doubt they would need 20k/month supply throughput like they claim they need.
Basically they want to sell you a new unit at high cost and bend you over and make you pay just because they can.

[cncts11]

This is why we have spent a significant amount of money and time to develop full repair and testing of BLD, BLIID and newer drives; the cost from Okuma for this older stuff is really high. The irony is that they are great machines and are built to last for a very long time, but then they actually start to outlast the support. For the controls and drives, we have fully functional simulators and full support. If you need help or parts, you can email me at [email protected]. Please note: even if you have diagnosed the problem, we do not sell top boards (or base units) separate from each other with a warranty. We do provide full 1 yr warranty on drives (exchange or repair) but they go out as a set - top board and base unit together. We will also do repairs, but again, if you want a warranty, it must be the entire set. We have done/can do just the board/base unit for customers, but we do not provide a warranty (as we don't know the condition of the mating part).

[WGJ]

I have sent the Z-Axis top board off for repair. I found a similar company a couple of states away that repairs them and offers a 3 year warranty along with a 10 day or less turn around. I will report back once I receive my board and verify that the problem is repaired.

[WGJ]

I am just now getting back to reporting the outcome of the resolution. The company I used repaired the top axis driver board and the LB-15 went right back to work. I am attaching a pic of the parts on the board that were replaced by the company.

[ncbobbys]

Where did you send your board for repair?
Thanks

[WGJ]

ERD LTD, Inc. in Kernersville,NC.
ERD: The Leader in Industrial Electronic Repairs

Great to deal with.

[ncbobbys]

Are you still having problems here?
Email me [email protected] for some help

[WGJ]

I appreciate the offer but it is working now. My top board on the z axis drive stack was repaired and the Okuma is back in action. The board was gone for a couple of weeks but it was around New Years so no harm.

Are you a tech?