Fanuc Ot - axis detect error

[bengineer08]

Yep, I've got notes on everything I've done, and when I swapped in 'new' components I've kept the old ones just incase. No trade ins or send for repairs, just so that I had the option to retrace my steps (I know it'll end up costing me more, but I wanted to be able to undo as much as I could). Once it's fixed I was planning to sell the useable leftovers to Radwell to recoup as much as I could. I sold some surplus PLC stuff to them in the past and that seemed to work out okay.'
I was able to dig up a Fanuc Connections manual online that applies to this O-Tc, and if I'm reading those tea leaves correctly, it could possibly be configured with just the one power supply (I think?).
So, at this point I'm not sure what else to do but try a new power supply and cross my fingers.

 

[Ox]

Not sure which "power supply" that you refering to, but as far as the 24, you want to unhook the leads from it and make sure that it is dead with no load.

I have seen it appear that the 24 PS was DOA, when it was a wire or component that was shorted - pulling down the whole thing, but not blowing anything.


---------------------

Think Snow Eh!
Ox

 

[latheman78]

Yep, I've got notes on everything I've done, and when I swapped in 'new' components I've kept the old ones just incase. No trade ins or send for repairs, just so that I had the option to retrace my steps (I know it'll end up costing me more, but I wanted to be able to undo as much as I could). Once it's fixed I was planning to sell the useable leftovers to Radwell to recoup as much as I could. I sold some surplus PLC stuff to them in the past and that seemed to work out okay.'
I was able to dig up a Fanuc Connections manual online that applies to this O-Tc, and if I'm reading those tea leaves correctly, it could possibly be configured with just the one power supply (I think?).
So, at this point I'm not sure what else to do but try a new power supply and cross my fingers.

Oh my God, you said RADWELL, they were the place that passed bad components and failed good ones for me. They are a company that spreads themselves way to thin and over states their ability to properly diagnose component problems. They do not have the simulated controllers on everything from A-Z as they claim. This is not your fault, put the machine back to it's original issue before you started trusting them and we will start over.

You should list your location, you never know, a knowledgeable old geezer like me could be around the corner, that would be willing to help, for a couple cold ones and a pizza.

 

[wmpy]

Can you provide the part # of what you swapped to get the problem to switch from one axis to another? It might also be helpful to give the part # of the servo drive(s). Is there only one drive for all three axes? You mentioned a high current alarm at one point. Have you checked any of the suspect motors or cables with a megger? I have a BNC-34S with a 0T control that is probably set up very similarly, so if there is anything you would like me to check on mine, let me know.

 

[bengineer08]

latheman78, that's good to know. I was planning to sell everything I didn't need to Radwell under the assumption they would repair what needs repairing before reselling, but now I'm not so sure I'll be doing that. Don't want my current problems to be someone else's future problems.
Luckily I've only sold to them (once, in the past) I haven't bought any of these parts in question from them. They're all still from ebay though, so...

wmpy, When I change the servo (control?) board (A16B-1100-0330). This board plugs directly on top of what I'm assuming is the servo amp board. The original board gives 3 axis detect error (B axis), the new gives X axis detect error. Again, these are ebay purchases, so I guess it's possible that they each have the same issue, only on different axes?
I have not checked anything with a megger, I was originally thinking that getting one would be too costly to buy just to check this one machine, but I'm 3 different boards in now so... I did try to rule out the cables and motors by swapping them. The X and B are both the same size motors, so I swapped power cables (no change), feed back cables (no change), then put cables back as original then swapped motors (no change). I assumed if it was one of those items I would get a change at some point, but nothing. Finally after everything else didn't work I got new (not ebay) cables made for X, still no change. So I'm assuming at this point that cables and motors are good.
Servo (feedback?) board is an all-in-one (I think it's up to 4 axis, but this machine only uses 3). A16B-2200-036. Nothing seems to change between the old and the new when I swap between these either. This board is where the encoder cables land.
I've also swapped the servo (amplifier?) board (the motor power cables land on this one) A20B-1003-0864/01A. No change with this swap either.
I appreciate the offer to check anything. I'll certainly let you know if I need it.

I've got a friend who's trying to get a service business off the ground, so I think I'll let him take a crack at it for a day or so. Might see something obvious that I'm just not seeing.

 

[latheman78]

https://cnc-electronics.com
https://tieindustrial.com

Those are the places to go for Fanuc controls of your vintage. Radwell does not have simulators for what they sell and repair, the above places do. CNC electronics has a Charlottesville Va location, TIE is 15-20 miles south of Nashville Tn.

Both places will test an item and if it is bad put the money toward repair or exchange.
Last I used them it was $100-$200 per item. CNC Electronics was usually always cheaper and quicker. They take your item and install it in a simulator that is a controller hooked to all the servo motors and other items they operate. No guess work like Radwell.

Just Ebay the leftovers and sell them as is or offer a full refund including shipping if dissatisfied. You will get way more than Radwell will give you for it unless they have an immediate need.

 

[bengineer08]

I should have started there...
Thanks for the info. I'll be bookmarking those sites.

 

[wmpy]

latheman78, that's good to know. I was planning to sell everything I didn't need to Radwell under the assumption they would repair what needs repairing before reselling, but now I'm not so sure I'll be doing that. Don't want my current problems to be someone else's future problems.
Luckily I've only sold to them (once, in the past) I haven't bought any of these parts in question from them. They're all still from ebay though, so...

wmpy, When I change the servo (control?) board (A16B-1100-0330). This board plugs directly on top of what I'm assuming is the servo amp board. The original board gives 3 axis detect error (B axis), the new gives X axis detect error. Again, these are ebay purchases, so I guess it's possible that they each have the same issue, only on different axes?
I have not checked anything with a megger, I was originally thinking that getting one would be too costly to buy just to check this one machine, but I'm 3 different boards in now so... I did try to rule out the cables and motors by swapping them. The X and B are both the same size motors, so I swapped power cables (no change), feed back cables (no change), then put cables back as original then swapped motors (no change). I assumed if it was one of those items I would get a change at some point, but nothing. Finally after everything else didn't work I got new (not ebay) cables made for X, still no change. So I'm assuming at this point that cables and motors are good.
Servo (feedback?) board is an all-in-one (I think it's up to 4 axis, but this machine only uses 3). A16B-2200-036. Nothing seems to change between the old and the new when I swap between these either. This board is where the encoder cables land.
I've also swapped the servo (amplifier?) board (the motor power cables land on this one) A20B-1003-0864/01A. No change with this swap either.
I appreciate the offer to check anything. I'll certainly let you know if I need it.

I've got a friend who's trying to get a service business off the ground, so I think I'll let him take a crack at it for a day or so. Might see something obvious that I'm just not seeing.

Based on everything you've done, it seems to me that the servo drive is the culprit. If it were me, I would send it (the whole drive) to a repair house that specializes in Fanuc electronics like the ones latheman78 recommended. I can also recommend Tri-Star CNC in there. They have done many repairs for me, and I have always been happy with them. This is the way I would go because I'm willing to pay to get my machine running quickly. Also, I'm kind of a sissy when it comes to troubleshooting electronics. And if they don't find anything wrong with it, it's only a couple hundred bucks to get it cleaned and tested and realize you were barking up the wrong tree. Now if you're trying to save money and have time to spare, you could keep swapping parts and doing other diagnostic tests. Maybe try a third top board on the drive if you can find one on Ebay?

 

[bengineer08]

I know the lesson well, do it right the first time. Band-aids never work for long, if at all. Sometimes you need a little (expensive) reminder. Should have gone that route to begin with.
I've got a friend in service work coming over this weekend. If we can't figure it out I'll be getting a hold of one of the places mentioned. I'll try and remember to make a follow up post once we finally figure it out, just to close the loop if it can help anyone in the future. Thank you both for the guidance.

 

[wmpy]

I should mention that, in case you didn't know, all those electronics repair places have very good, free, phone tech support. I have had particularly great help from the guys at TIE that helped me with some complicated problems that even the guys at Fanuc weren't able to help figure out. And Fanuc has free tech support as well. They're good, too. I just wouldn't recommend getting any repairs done by them- too expensive.
If you do call someone for support, I wouldn't lay out everything you've done. It's a bit overwhelming. Just tell them the original alarm you got. Then explain how you swapped that top board and got a different alarm. That seems relevant. Then let them take it from there. They'll know what questions to ask. If they tell you to swap something, then you can say you've already done that.

 

[Vancbiker]

........
If you do call someone for support, I wouldn't lay out everything you've done. It's a bit overwhelming. Just tell them the original alarm you got. Then explain how you swapped that top board and got a different alarm. That seems relevant. Then let them take it from there. They'll know what questions to ask. If they tell you to swap something, then you can say you've already done that.

When I was doing field service, I'd typically turn down jobs where someone else had been in the machine dicking around much trying to fix the trouble. More often than not the original trouble was pretty minor but by the time boards got swapped, cables moved, settings changed, dip switches or jumpers moved, the original problem was now just a minor part of a much larger repair.

 

[bengineer08]

UPDATE for anyone interested, or with similar issues...
As I stated earlier, I replaced both boards individually on the servo drive and neither seemed to be the problem. I spoke with TIE Industrial, they had me send them the drive PCB (one of the ones I replaced). They checked it out and OK'd it. So I sent them the entire drive and they repaired it. There isn't much on the whole drive once those two boards are out of there, but there is something and whatever it was, it was causing my issues.
It's tempting to just try a $300 or $400 board off eBay, but if you're not lucky that first try it's a rabbit hole.
Long story short (lesson learned again), it's cheaper in the long run to have the professionals do it.