[starweldengg]

Hello!

Can anyone help with troubleshooting the RAM Parity issue in my Dahlih MCV1350 with Fanuc 11M control.
The error appears abruptly and very frequently.

Thinking of it as case of memory being corrupt, i have tried formatting the NC and reloading the parameters. The issue still continues.

Would appreciate some advice on pinpointing the issue in the NC specific to motherboard or other card details.

[fordav11]

likely you have bad RAM on the main board. the fix is to change that RAM or replace the main board

[memoryman]

The full message: ‘Ram Parity Error Servo CPU# 7’ I have no idea about that.

[underthetire]

Could be a bad bubble memory board. Replacement is a RAM board,, but on the bright side, you get more memory with the replacement.

[memoryman]

As someone who designed a sram based bmu replacement in 1990, I can say with some confidence that it is most unlikely to be the bmu.
There is working ram located on the motherboard. It looks like there are three separate alarms in one line:"Ram Parity Error", " Servo", "CPU" and possibly a fourth: "# 7"

[starweldengg]

Thanks for the responses! Just to clarify on the error, adding some images of the error and some NC screens.

[starweldengg]

Also, during the self test of the NC when turned on, the bubble type shows #19. Is this normal? Can some one please upload a scanned copy / pdf copy of the maintenance manual for Fanuc 11M.

Hey Fordav11! Can you help me locate the RAM chip on the mainboard with some IC number or so. As there are so many ICs on it, it is going to take me a millenium to google every IC number to find out the chip.
See image of the first screen here: Attachment 276766

I had asked one of the local technicians / mechanic to help me fix the issue. He suggested that some electronic component in machine is getting overheated and asked me to place a cooling tower fan in front of the panel. And out of desperation i tried it, it did not work.

[fordav11]

as they said above it looks like the bubble memory board is bad. just replace it.

[starweldengg]

Here's an update friends:

I got my 11M motherboard and the cards tested by an ex-Fanuc (India) service guy. He kept the motherboard connected to his test jig for 3 consecutive days and witnessed absolutely no error messages or any faults. So, I got the package back and fit it again in to my NC. The problem stills exists at my end. The service guy is asking me to do a partial retrofit and switch over to Fanuc OM-C which costs a bomb. At that point, i felt like i m being cheated by the service guy and he just wants to sell me a new control.

Later, i consulted a few trustworthy friends who also have had CNC machines with old controls in the past and faced issues with the control and later switched to a newer control. They said that getting the card repaired is just a temporary solution and the problems re-occurs in a couple of months or so. Also they said that upgrading to a newer control will help resolve any control related issue as well as improves NC performance.

I have somehow been convinced by those friends to upgrade the control. But before I take this step, I would like to have a piece of advice/suggestion/warnings from my virtual friends on this forum.

P.S.: I have also contacted Fanuc directly, but after a sluggish unsatisfactory response from them, i decided the above mentioned way.

[memoryman]

Something isn't right. How much do they want or the retrofit? That is not a simple job, especially if the servos/motors require changing.
Did you replace the BMU?

[starweldengg]

They are asking for INR 300,000 (~ USD 4700) which includes the cost of the control and the fitting charges. The servo motors would not be changed. Only parts that would be replaced are the motherboard (& attached cards) and the operator's control panel (including the CRT).

I have contacted and explained this issue to at least 15 different mechanics / card repairers and shown the issue to at least 5 people. None were able to give me a definite response that assures me of the problem being solved. I have already lost big bucks just paying for the visit and inspection charges for these people. I asked them to replace the BMU card, none are willing to or even suggesting to change any of the cards. Unfortunately for the Indian NC owners, there is a bad situation here. With this learning experience, i come to understand that there is a horrible network setup by the servicemen, card repairers and the mechanics who do retrofitting to loot the NC owners. Everyone is linked, and suggest the same solution.

To add to that, responses from Fanuc team is very much unsatisfactory. Fanuc charges roughly INR 5000 (~USD 80) for a minimum 2 hrs visit. Later they will charge INR 1800 per hour (USD 35) for the issue to resolve. Well that is still OK with me. But when i asked them how much time would it approximately take to service the card, i got a poor or rather scary response. They say it may take a few hours or even months in case there is a software issue with the motherboard. This was pretty much unacceptable. Further, i asked them to link me up with their sales team, so i can talk about upgrading the control. It's been more than a week but no response from them. No one even picks up the calls on Fanuc's landline number.

Feeling all stressed.

[memoryman]

Sad situation; in North America it is much different.
Why not buy a BMU off Ebay and try?

[fordav11]

$4700 is not a bad price for the complete repair.
and $80 for 2 hours! you are lucky! I wish it was that cheap here. Fanuc and Okuma charges $75 per half hour for labor. In fact here it is not uncommon for most businesses to make $1000 per day in labor charges.
I agree with memoryman. buy working board off ebay. just be sure it is sold as working and that you can get refund if found to be not working when fitted.