[wagner63]

Hello Everyone,

I've been surfing around here for some time, but this is my first post. Great site, lots of great information.

I recently bought a 1996 Fadal VMC15 (CNC 88HS control) which currently resides in my garage. It is wired to run off of 240V single phase, and has been running this way successfully for a few months. I am getting to the point where I'm finally making some chips, and a few issues have popped up as I've run the machine more.

Issue #1: The machine was getting harder and harder to power up first thing in the morning. I would turn on the main power, but pressing the brown out button would take multiple attempts, I would have to power up, power down, etc. to get it to initialize. I just swapped in a new DC power supply, and so far this problem seems to be resolved. I'm fairly certain this is unrelated to issue #2, but I mention it just in case.

Issue #2 (the real problem): I am having intermittent faults coming up when running a program, sometimes jogging, and once or twice even while sitting still (motors were still enabled).

I am getting an "Emergency stop, take appropriate action" fault intermittently. Usually this is the only error message, that's all it says, which is what makes this frustrating. No motor faults or fault numbers to come up to accompany the message. Once the fault comes up, the X and Z retain their positions, however the Y will have reset itself to zero, even when the Y axis actual position is clearly way off of the witness mark.

I can hit Jog, the servos will come online again, and everything continues to work normally. The only exception is the Y will be reset to zero wherever it was last stopped.

Once or twice while jogging, I was lucky (?) enough to get an actual error message, it was "Y axis fault #26, motor overload" which I understand to be a following error. The machine behaved exactly as it did when i get my ambiguous emergency stop errors.

I wrote a test program which moves the X and Z off of zero, then jogs the Y full traverse in an endless loop. I'm running at 50% rapids in the test program so nothing extreme. Sometimes the program will run for 3 minutes from a cold start and fault, sometimes for 3 hours. I haven't completely ruled out the fact that I am running off of household voltage so maybe something is kicking on in the house and causing a power issue? Seems odd to me the Y is always the one that faults though.

On another note when I get the fault, all of the amp boards are not lit up, except for the X which flashes red very sporadically. I thought this was odd, but then noticed the X always seems to flash red sporadically when it's not enabled, even when the fault doesn't come up. The Y and Z LEDs are off completely when not enabled, until everything is enabled then X/Y/Z are green across the board.

Any thoughts? Sorry this got long, I'm an engineer so I can't help it. Thanks in advance for any help anyone can give.

Matt

[wagner63]

First of all, thanks to everyone who PM'd me to help me along.

I did a bunch of troubleshooting and here are the results:

-Swapped the X and Y amplifiers, still got an e-stop fault with no further error messages, Y axis still lost its zero in the process. Ruled out the amps.

-Swapped the X and Y axis control boards, still got an e-stop fault with no further errors, now the X axis lost its zero in the process. The problem seems to be on the Y axis control board somewhere.

-Swapped back the X and Y axis control boards to their original positions. Swapped both EPROMs between the X and Y boards. In other words the axis control boards are in their correct spots and the EPROMs are now switched between X and Y. Got an e-stop fault with no further error messages, Y axis lost its zero in the process, the problem did not follow the EPROMs. From what I'm gathering the problem appears to be on the Y axis control board itself.

I looked at the board as close as i could for bad solder joints, etc. I am going to look further with a loupe soon to see if i can spot anything.

**Does anyone know anything further to check before I shell out big bucks for a new control board? Common components that go bad, things to check, etc?** I am comfortable with a soldering iron so I'd rather spend a little time myself first since this is a side project for me.


Thanks in advance

Matt

[BenTreamer]

Suggest swap y motor with the x or z motor--if the problem follows the motor then you probably have a bad resolver.

As far as issue #1, I had a very similar problem for the longest time, probably for at least several years...finally I swapped the 1040 card from a different machine into it and the problem disappeared.

One last thing--don't "park" x or y axis at end of travel for any extended period of time unless you've checked your extreme over travel springs for proper adjustment--otherwise, you will be putting pressure against them which will rapidly cause motor overheating

[wagner63]

Thanks again everyone for your input and PMs. I actually witnessed the problem from start to finish the other day. I had the E-stop circuit jumpered out by doing the F16 to F12 jumper, not sure if this helped me see the problem or not. I figured I would describe it in case anyone else has the same issue.

1. My test program was running normally jogging the Y back and forth.

2. The program stopped executing, the Y stopped moving. No error was on the screen at this point yet.

3. I looked in the electrical cabinet and the Y axis controller board's light was off completely. All of the other boards were flashing red as usual.

4. After about 10 seconds the Y axis board came back online (red light blinking again). When this happened the E-stop error came on the screen. I guess this explains why i wasn't getting any error messages from the axis, since the card was resetting itself or so it seems.

Anyway this was proof enough for me, and since the problem followed the card when I moved it a while back I'm pretty sure that's whats wrong. I have a new card coming next week I'll post the results when I install it.

[wagner63]

Thought I would post the resolution to this - new Y axis control board was installed yesterday - problem solved. I swapped my EEPROM's and jumper from the old card. The machine ran for 6+ hours nonstop without a fault (run time before was usually about an hour before it stopped). Thanks again everyone for your help.