[Sailor]

I just found this site a few days ago and am impressed in the amount of knowledge and willingness to help. I hope someone can help with a problem I am having.

I have a 6M running off a 30hp phase converter. Upon power up I get a System Error 999
242 ** System Error
997 241 32 242 18 251 A4
252 BB 261 93 262 C4


Any help would be greatly appreciated.

[Dan Fritz]

Your control is detecting a bad or missing EPROM chip on the ROM board. There should be a board marked "ROM" that's plugged into the main mother board of the CNC. This ROM board has a bunch of EPROM chips that contain all the executive (firmware) in the control. The alarm is also telling you which EPROM chips have the problem:

These are 8-bit EPROMs, but the control uses a 16-bit processor. The EPROMs are read by the processor in "pairs" (8 bits from one EPROM and another 8 bits from another EPROM are read simultaneously, to make a 16-bit word). The two pairs of EPROMs the control sees as a problem are marked on the board:

EPROMS 241 and 242 (this is a "pair")
EPROMS 251 and 252 (this is also a pair)

Check to be sure that these 4 EPROMS are securely seated in their sockets. They have a tendency to wiggle loose from the sockets over many years of hot/cold cycles.

You can safely remove the ROM board from the control and put it on a bench. Just be sure to keep chips & coolent off of it. There is nothing on that board that requires battery backup.

If these 4 EPROMs aren't plugged into the board at all, then you have a situation where there is an option parameter in the control that is telling the processor to go to a specific address, but the EPROMs aren't installed. This usually happens when someone tries to install an option parameter that shouldn't be in there. The only way out of this mess it to delete and reload all the parameters, and avoid putting in any option parameters that weren't originally purchased with the control.

If you replace or add any EPROMs, you will have to be sure that they match the software series and version numbers marked on the chip itself. The first number is the software series, the second number is the chip location on the board (like "241" and "242", above). The last letter is the version, and that determines how old (or new) the software is. Fanuc can send you a complete SET of EPROMs, but I don't think they can send you just one or two from an older version. If you find someone else with the exact same EPROMs, you could make copies of theirs with an EPROM writer, but it's unlikely that you'll find a control with the exact EPROMs that you need.

Good luck!

[debco99]

Dan,

After being in this business (controls) for er over 30 years (yikes) I always enjoy and learn something from reading your very helpful post's.

I have worked for various machine tool builder's and control builders (remember UMAC)? hate to date myself, but it's nice to have people like you in a forum that really have answers for people and get them heading in the right direction.

I have all the schematics for the 6 series control so if anyone is interested in them I can copy them , however I would like to make up 4-5 sets at a time and just cover the cost of making them up.

Keep up the good work Dan

[Sailor]

Thanks Dan.
I believe I have the correct board, labeled PC/PUNCHER. It has six EPROMs
on it. They are labeled
B00 241E, B00 242E, B57 251B, B57 252B, B57 261B, B57 262B.
They all seem to be tight and clean.

Would I be better off buying set of EPROMs from FANUC or just buy replacement board from somewhere like Tennessee Industrial Electronics.
Also, if I replace EPROMs or board will I lose any information.

Thanks again for all your help.

[Dan Fritz]

Sailor:

By golly, you're right. Those EPROMs are not on the ROM board after all. They're part of the "PC model A" The "PC" is the Programmable Controller that contains the interface logic (Ladder logic) for the control.

Sorry, I should have looked at the schematics to see where these EPROMs were exactly before responding to your post. The main Executive firmware is on the ROM board, and only the firmware for the Programmable Controller functions are on the PC/Puncher board. That board also has the serial and Facit parallel commuications circuits on it, which is why they call it the "PC/Puncher" board.

Has anyone replaced this board lately? If so, you may just have a version conflict between the EPROMs on this board and the ones on the ROM board. All the EPROMs in the control must be of the same series and version. If you need to replace the PC/Puncher board with another one, be sure to unplug those 6 EPROMs and plug them into the new board.

[Sailor]

Thanks Dan.
This is the original board. I believe the only board ever changed is bubble memory years ago.
Does this mean the board is bad or the EPROMs or both.


Thanks again for the quick response.

[Dan Fritz]

I would check to see if the chips are just wiggling loose first. Put the board on a clean surface (use a clean towel or shop rag), and press on each of the EPROM chips to be sure that they're seated in the sockets. Also look very closely at all the pins to see if any of them are "Bent under" instead of plugged into the sockets. A bent-under pin can make very intermittant contact. You can usually remove the chip by prying on both ends equally with a small screwdriver (very carefully!), then straighten the pin and plug it back in. Don't remove an EPROM unless you see a bent under pin.

I wouldn't replace the whole board if you can get the correct EPROMs from Fanuc or elsewhere. This board very seldom fails.

[bertcnc]

Hi
I am interested in buying a copy of your fanuc 6 series scematics.I also need diagrams for the 10TF. It won't boot up (8 displayed)-looks like a problem on the ACP card -If you can help please. email. [email protected]
Thanks in advance.