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Fanuc Modes- Auto, MDI, JOG etc OMD

Getting alarm 434 almost immediately on power up is most commonly a short somewhere. Bad cabling and connectors is common. Does the axis drop a few mm? If so it likely just gravity acting on it before the brake re-engages due to the servo alarms.
 
You are probably right. Best I remove the spindle column so there is no weight before I go any further.

When you power on, do the servo drives do a small 'giggle' to confirm that they are active ?

If not, why would the brake be releasing if it wasn't going to move. Maybe the brake is off all the time once the system is on.
 
Maybe disconnect the brake power and see if the machine still faults.
Nope. The brake is energized to release. Spring actuated when de-energized. If you disconnect the wire it is always engaged. The brake will be released (energized) any time the servo are powered and in the ready state.
 
If the servo is faulty, then releasing the brake would cause it to move and I'd get the fault. So, my thinking is remove the brake lines, power on and then I should not get any movement and no fault. If this works I can try and load the macros etc because at the current time, I don't seem to be able to send or receive programs. I assume it was the fault not ready issue.
 
Fairly sure the machine is only moving after the alarm happens.

Does the machine have a counterweight for z? Or does it have a hydraulic or pneumatic counterbalance?

I suggest being very careful working on z. You seem to have a good handle on it but messing with z can be dangerous. Be sure to block the spindle and counterweight so nothing falls



You could put the screen on the servo tuning page (one of the pages that shows up after hitting the parameter button a few times) and page down so you can see z axis load, before you disengage estop.

Of course i would also get a megger and check the motor and cable.

Does the drive in back show an alarm?

Just want to say, the course this thread has shown so far can be a reminder that being methodical when diagnosing is important. If most people started, fire example, pulling out eproms when trying to fix a "not ready" alarm, there would be a lot more dead machines out there. You're lucky you were able to figure out how to resolve that. No offense, you have enough skill to fix your mistakes, but i think you know just enough to be dangerous; it's easy enough to do damage and generally costly to fix it. 😉
 
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I'm trying to input a program now and the reload the macros.

Must PWE = 0 and KEY = 1 to load programs ?
Last time I set KEY to 1, I could not change it back to 0.
Currently pressing INPUT does nothing. INPUT and my cable does work as I loaded the parameters with same machine.
 
If most people started, fire example, pulling out eproms when trying to fix a "not ready" alarm, there would be a lot more dead machines out there. 😉
Good info. Pulling the eproms was so I could turn on the ladder logic view (bypass password) to help diagnose the "Not ready alarm."

I have Fanuc Ladder II software and a WIN 98 machine but there is something wrong with the graphics. It is like the screen should display a prompt like -> but shows ^%$>< instead. Tried a VM machine as well, all does the same. Makes it unusable.

Its late your side of the world !!!
 
Finally got a video on the Z fault..
Z-Fault


Screen come up with
401 Servo alarm (Vrdy off)
430 Z axis Excess ERR
434 Z Axis Detect ERR.

All the wiring seems to be ok.

Drive is A06B 6080 H305

Not sure which connectors go to the Z encoder short of pulling the cables out.
 
If one of the other axis drives is the same model you can swap them and see if the alarm follows the drive. There will be 2 or 3 connectors on the motor. The one furthest from the mounting flange is the encoder. The other will be the motor power and if you have a third, it will be smaller and is the brake. Some builders spec a servo motor with built-in brake while others use an external 3rd party brake.
 
I did think of that but the Z is much bigger, I presume for the spindle weight. Also has a brake,

A068B 0373 B077 0.5 KW
A068B 0127 B177 1.0 KW

Looking at prices of spares, I could easily sell the bits for more than I paid for the whole machine.
 

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Yep, no swapping the drives then. Here is another thing to try. Prop up the head so it cannot drop. Disconnect the motor power wires (U, V, and W) at the drive and power up the machine. If you still get the 434 alarm then start looking for a replacement drive as it has an internal fault. Most commonly a bad transistor module.
 
I put a jack under Z and no error. Green On light came on. First time. In MPG mode I got the x to move a few mm and once I went to Y, got 421. Switched off and back on again, X gave an error as well.

Any chance that the servo parameters are wrong and causing the fault ?
I need to check that I have 3 phase coming into the drive. Maybe the contactor has a bad contact. Looking to replace it with a solid state one soon.
 

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3 phase all good. Something common. Guessing parameters. I don't have a PMC file, but after loading Parameters, the diagnostic data and servo drives all got values from some where.
 
This what I have from the manuals. Doesn't look very much.
 

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Finally I can boot the machine without errors. Didn't realize it but the limit switch was actually flaky, sometimes on sometime off. Stripped and fixed it, so it boots every time now.

What I can't understand is when you have a fault it disables the serial comms.

I managed to dump the diagnostic data and for the first time I see it starts at N10300 and ends at N10589.

I have no printed data on this. Any suggestions?

I also can't load programs. Get error 087. Bit strange as it loads and dumps much bigger files without issues.
 

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I also can't load programs. Get error 087. Bit strange as it loads and dumps much bigger files without issues.
What is the setting of parameter bit 391.6? This sets whether DC characters are used for Handshaking. Coupled with that, what is the pin out configuration of the cable being used?
Regards,

Bill
 








 
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