[Gareth52]

Hi can somebody help me please?
I built my CNC machine about 14 years ago. Up until about 2 months ago, the machine had run perfectly. Then, when I switched it on, none of the axes would run properly. The motors would jerk and move just fractions of an inch. There was a bleep, bleep, bleep sound coming from the motors instead of the usual high-pitched whine. After 20 – 30 minutes, the high-pitched whine would return and the machine would work perfectly.
Today, the machine did not work at all.
Because all 3 motors have the same symptoms, I believe the problem is in my control box. The stepper drivers have been working perfectly, so I am left to wonder if it could be the breakout board, or the charge pump.

Can anybody suggest what it might be, because I am a little challenged when it comes to electronics?

Thanks,

Gareth

[Jim Dawson]

You give no details about your machine, so any answer would be a wild guess. Power supply maybe?

[Gareth52]

I examined my CNC control box today. It consists of the following components: –
3 leadshine stepper drivers
1 breakout board
1 x 12v/5v power supply
1 x 68v power supply

When switched on, everything tested okay. But then I connected the control box to the PC and Mach 3. As soon as the reset button on Mach 3 was powered on, all 3 stepper drivers started flashing red. This indicates a fault. I tested the power supply, which had been previously reading 68 v and it was reading overload. As I said before, I am electronically challenged. My gut instinct is that it's the breakout board.

Can anybody offer some advice please?

Thanks, Gareth

[Jim Dawson]

It could be the 68V power supply is failing, or maybe one of the drives has failed. I would disconnect power from the drives, one at a time, to see if a drive has failed. I would not expect the breakout board to cause the symptoms that you describe.

[Gareth52]

It could be the 68V power supply is failing, or maybe one of the drives has failed. I would disconnect power from the drives, one at a time, to see if a drive has failed. I would not expect the breakout board to cause the symptoms that you describe.

Hi Jim, you were right: – it was the 68v power supply. My friend put an oscilloscope on the power supply. As soon as a load was applied the signal crashed the whole thing went crazy. Fitted a new power supply today and everything working fine.

Thanks for your help,

Cheers, Gareth

[Jim Dawson]

Happy to hear you got it going again. :cheers:

My pleasure to help out where I can.

[Al_The_Man]

Hi Jim, you were right: – it was the 68v power supply. My friend put an oscilloscope on the power supply. As soon as a load was applied the signal crashed the whole thing went crazy. Fitted a new power supply today and everything working fine.

I'll bet it was a SMPS version, I never use those for AMP power, the linear variety are a little more $$$ but worth it in the end, it often comes out even after you have replaced a few!
Even most of the drive manuf. agree.
Real easy to fix, IF they ever do quit!