[BillyDoc]

I have a Fanuc 6M-Model B controller in a Shizuoka Mill that was working well, was not used for a week or so, then when re-started would not boot up. I did some trouble-shooting and found the alarm (red LED) on the Input board lit up, and found that when I disconnected all outputs from the Power Stabilizing Unit (A14B-0067-B002) the alarm went away. I tested further then, using a Fluke multimeter on ohms, I found that the 24v output pins were shorted (zero ohms) to the ground pins. This short turned out to be between the 24v pins that are the left-most two pins on connector CDP, visible in the photo below on the upper right-hand corner of the I/O board, which is a Fanuc A20B-0008-054, and the next two pins to the right, which are both GND.

With the I/O board (A20B-0008-054) completely removed from the system and nothing connected, the short remains as measured at the power connector pins of CDP. Visual inspection shows no anomalies. This I/O circuit board is a multi-layer board, and there are no traces visible from the 24v input pins, and with a zero-ohm short everywhere I test the resistance from ground to either 24v or another ground point my ohm meter reads the same zero ohms and I cannot distinguish which is which.

So my question is simply this, does anyone have or know where I might find a circuit diagram for this A20B-0008-054 board? Or, have any idea how I can find this short without that circuit diagram? Or just know where the 24v is supposed to go? I am completely stumped about how to proceed at this point.

Thanks for your help!

Bill

[Al_The_Man]

If you disconnected all I/O Honda plugs and the short disappeared it seems it would be on one of the I/O, disconnect them one at a time to see which one causes the short, if this is the case.
The usual failure of output and input component on the board usually mean that either a output stays on or an input reads 1 instead of zero.
Al.

[BillyDoc]

Hi Al,

Thanks for responding!

Yes, the short disappeared from the Power Stabilizing Unit when I disconnected the output lines, and I then tracked it to the I/O board (A20B-0008-054). All the other boards seem fine. On this I/O board, however, the short is zero ohms so I can't differentiate the 24 volt traces from the GND traces. Both of them give me zero ohms to GND. I think if I knew where the 24 volt traces went I could track the short down, but I have no circuit diagram.

Do you know where a circuit diagram might be located?

Thanks,

Bill

[memoryman]

I have the diagrams scanned in; send me a pm with your email address.

[BajaCat]

We have a Shizuoka B3V MillMaster with Fanuc 6M controller that seems to have had the Bubble memory erased so we have no parameters. Neither do we have a copy or any manuals. Does anyone have the same machine that could help me with parameter Data?
Thanks
BajaCat

[BillyDoc]

BajaCat,

I have the Fanuc 6M controller manual, but don't have parameters for your machine, or mine for that matter. I've just been looking at Appendix six in the manual and each parameter is described, but usually not in enough detail to generate specific parameters for specific tools, at least at my level of understanding. I also have not been able to find a contact with Shizuoka, as they probably do have the information we both need.

If you would like, I can at least scan Appendix six to a pdf file (or series of files) for you, and maybe you can sort it out from there. I can't manage it. If you want me to do this, PM me with an email address and I'll try to get it done monday.

Bill

[BajaCat]

Bill,
That could be very helpful email is [email protected]
Vince

[RichmondLabs]

Hi Al,

Thanks for responding!

Yes, the short disappeared from the Power Stabilizing Unit when I disconnected the output lines, and I then tracked it to the I/O board (A20B-0008-054). All the other boards seem fine. On this I/O board, however, the short is zero ohms so I can't differentiate the 24 volt traces from the GND traces. Both of them give me zero ohms to GND. I think if I knew where the 24 volt traces went I could track the short down, but I have no circuit diagram.

Do you know where a circuit diagram might be located?

Thanks,

Bill

Exact same problem... Anyone ever figure out the cause of this?

Richmond