Need Help!- Alarm code 234 spindle cable fault

[morpwr]

Need help please. I have a 1998 Haas VF3. Last 8 months, would get a 234 code, spindle cable fault. If I reset, would go away for a day or a month. Now comes on after machine is powered up, when I start to run a program. I also occasional get a 235, Z axis fault. I also now get a 112, interrupt alarm. This alarm you cannot reset. The machine has to be powered off then on to go away. Any suggestions please.

[DaOne]

Sounds like a power supply issue to me. This can cause the 112 alarm. Test the +12, +5 and the -12 VDC on the low voltage power supply. Alarm 234 means your spindle encoder does not have valid differential signals. This can be the mocon, the cable, the power supply or the encoder. Alarm 235 is a spindle encoder marker count failure. This can also be the same as alarm 234. Since you are getting alarm 112 I would make sure the voltage going into the mocon is correct first. Next check the cabling especially in the track for damaged wires. They move with the Z axis and can fatigue over time.

[Wizzard of H]

All of the symptoms you have could be a power supply but are more likely a cable problem still. These things flex continuously and after about 13 years, something can break. Look very carefully for damaged or contaminated cables to spindle encoder and anything else up there. A cable with 5 volts shorting to ground could cause a lot of other things that look like power supply problems.

[Haas__man]

Just as wizard said earlier - the spindle cable fault is probably exactly that, a fault with the cable, probably where the cable plugs up in the head.

As for the 'no interrupt' alarm - this is what I suggest you do.
Open the electrical cabinet door with power off.
Look near the top right for a PCB with circuit breakers on it. The circuit breakers will be labelled for coolant and main transformer and CB4 115v. This is the POWER DISTRIBUTION PCB.
Look at the left side of the PCB and you should see two cables that look the same. One goes to the processor and one goes to the mocon PCB. unplug each one and plug it back in - you could do this a few times. You should find that this will temporarily fix the fault - but it will come back again. If this works I would suggest you buy two new cables from HFO. I can get you a part number if you need it.

Hope this helps