Need Help! Fanuc 3M-C

[Swemill]

My Kitamura Mycenter1 with Fanuc 3M-C is not working….. It all began after I had used the machine some hours and it stood still, but was on. Suddenly a “bam” was heard, exactly like then I put in the emergency stop and the screen was all dark green (like the text). I turned off the control and then on again but now doesn’t the screen show anything…. The alarm / tool number window is also out and nothing can be done with the control like handle movements, manually coolant etc. All led’s like single block, optional stop etc seems to work.

We have checked all fuses, relays, phases, 360 – 110 – 24 – 5 volts power supply / units and they all seems ok! The emergency stop is tested and ok (but seems not to work in the circuit like it should).
We have even tried to force the “RADY” relay but that’s not helping to start the control…. It seems like there is missing some “ready” ? signal from board circuit to start the control?

I’m now afraid that it’s some of the Fanuc boards that needs to be exchanged and that it costs more than the mill is worth……. Have any of you Fanuc guys any tip or proposal? The machine is otherwise in very good condition but unfortional very old (-83).

[f-bu]

- have you checked the cnc power supply? +5, +24, +/-15V?
- any red LED on the mother board lit?
Try disconnecting all the cables from the cnc exept video cable and try again(I mean M1, M2, 6,7,8,9, 18, 19 etc.) If there is a short somewhere, the cnc should start

[Swemill]

Hi
I have not very good electronic skills and a friend helped me with the measurment and faulty search but yes, i'm pretty sure that all voltage was checked at the power supply!
I belive there was both red and green LEDs on the motherboard.
Dumb question, but where is the cables you mention? Motherboard? Power supply?

Thanks for your help!

[f-bu]

On the motherboard the connectors are marked with white text, for example on the left side upper one is M1, in the middle M2, down is M3. Along lower edge are located 20 pin connectors to the servo, from the encoders, video signal is the last one. On PC1, PC2 additional boards you will find M18, 19 etc. LEDs are also named, check it.

[Swemill]

Ok thanks, i will check this tonight.
The "video cable" is the connection between the cnc control (display) and the motherboard?
Then i will dissconnect and try start up the cnc for each cable.
What does the red LED on the motherboard indicate (more than parameter write enable)?

I'm very thankful for your help! I'm really afraid that my cnc is going to be metal junk.....

[Swemill]

Have now done some more tests and have measured the power unit again. The voltage seams ok but I don’t know if it’s necessary / how to measure the “CP32” – 6 pin connector (-15, 0, EN, * PF, O, +15) on the power unit!? Does that need to be measured if the other (pins above) is ok?

When I power machine on I get: “2DLS”-relay LED on (and on control panel). With the emergency stop on I have: “EMG”-relay LED on.
When I start the control I get: “CR1”-relay LED on (and still “EMG”-relay with the emg. stop on). Green “PIL”-led on at the A-20B-1000-069 board (no red alarm code led on). Also green “RDY”-LEDs on at all three servo.
The red “parameter write enable” LED does not turn on with switch on motherboard, but the other red and green LED’s on mother board goes on with the power.

Have disconnected M1 – M12 cables one by one on motherboard + M18 and M19 on PC1 (no M20 – M21 connected on PC2). The M5 cable were not connected..? Also tried with the CRT / CCX cable. Are not sure wich the “last one” – video signal cable is!? There wasn’t any other after M12 / M19? Is it the “CRT / CCX” cable? There also is a “RAM – M41” connection between mother board and memory board and a “black – white – brown” on top of motherboard.
However nothing was changed with the disconnection…..

Is it failure in the motherboard? Help Wanted please!

[MysticMonkey]

Sounds like either the CRT or the video feed is faulty

[Swemill]

Yes maybe, but would the CRT make the control "die"? I can for instance not manually start the coolant now... or move any axles? The glass fuse behind the screen is ok.
Can i test the CRT and video feed someway?

[Swemill]

Does anybody have some info that can help me? I'm kind of stuck here...
The M5 cable goes to the tape unit so thats why it wasn't connected, but which is the video cable? Is it the CRT / CCX or maybe the M19? There is a lot of M-cables connected from motherboard to the control...
Can i do any more test to find out if it's failure in motherboard, CRT or video feed?

Thanks in advance!

[Swemill]

This is really depressing. I cant afford any Fanuc repair.... And then the christmas gifts i had plan to mill for the family... I'm now have thoughts about the alarm / tool number window. Where does this info come from / what could cause that failure?

[Swemill]

Some new info:

It seems to be the same fault whatever I do… Have measured the output voltage again on the power supply and it’s ok (even the “minus” voltage).

Disconnected all cables to motherboard.

Tried with only CRT cable connected.

Tried without the ADD MEM board.

Tried without the PC2 board (A20B-0008-0640 A).

Tried without the PC1 board (A20B-0008-0630 A), and it’s all the same…

No CRT screen and alarm / tool number display. No function works on the control. The red LED2 on motherboard (A16B-1000-0010 / 08F) lights in all tests when I turn the control ON (the green besides lights as well). The "Parameter write enable" - switch doesn't turn on it's LED.

There is no visible or smelling failure on the boards…

I understand it as a Motherboard or PC1 board failure?, but is there any way to tell which?

And also, what does the LED2 on motherboard stand for?


Thanks in advance!

/Joakim