All or some steppers acting weird.

A new problem has cropped up after years of my CNC working fine. I'm guessing it might be lightning storm related. (something got shocked and damaged)

My CNC, custom built 3-axis, HobbyCNC driver board, transformer/rectified/capacitor power supply, LinuxCNC (when it was EMC3) on a Thinkcenter M52 (P4, 3.0ghz).

I hadn't used the cnc for a few weeks and I went to use it and when I got everything powered up, I thought the stepper whine sounded different. When I went to jog the axes around (all 3) they sounded very bad and gravely. It would start loosing steps at a very low speed and clearly had very little torque.. I shut everything down and blew everything off (dust on the board and in the computer) and retightened all connections and when I booted up again, it seemed to be back to normal.

Then a day later I started it up again but now it seemed only the Z was bad, or sort of bad. I milled a few small things and I think the Y axis then went bad again and the part showed lost steps in Z and Y.

I check the unloaded voltage of the power supply and it was about 40v, which is correct. I also checked the 5v test point on the HobbyCNC board and the voltage pad for each motor and they were correct.

I'm trying to find a replacement computer, but can a parallel port be "sort of bad"? And would the CNC sort of work, but not correctly? What else could case this?

Thanks

Yeah I guess that makes sense. It's a power supply made from a transformer, rectifier and cap as per HobbyCNC instructions. I'll try changing out the cap. My only other easily accessible DC power supply would be some LiPo batteries (RC hobby), I could put those in place to test also.

Although I did check the power supply out voltage (not connected to the driver board) after turning the transformer off and it was retaining voltage for a good half minute slowly dropping from 40v to 1 or 2v. There is a resistor on the cap to discharge it I think, so that would indicate to me that the cap is ok. I think I have some other big caps I can try though. I'll go through my wiring on the power supply too.

Thanks.

The stepper config has setting for the HobbyCNC board. As far as I know nothing changed, which makes me think it's a hardware failure that may have occurred during all the lightning storms recently. But I'll do some testing tomorrow.

That computer has some weird latency issue that was SMI or related. It had a huge spike in latency every 32 or 64 seconds, but I fixed that with some SMI or similar thing in the config file. I think I had the latency setting at 50,000 or so. I would get errors occasionally while running the CNC, but I never noticed any major problems with the parts made. I've literally run the machine for days, surface finishing molds and had no problem.

Oh I forgot, I tried a different power supply (switching?) years ago and I think that caused some weird ground loop, that may have overloaded something in the computer. But again that was a long time ago, and it's been working fine for years.

I'll still try power supply testing, though.

I've seen the problems you describe from bad wiring between the drives and motors, bad plugs, and bad drives. (and those 1st two problems can cause the 3rd.)

It appears to be working...now that I have the printer cable secured to the computer port properly. After futzing with it I noticed one of the two standoffs screwed into the computer port ends (little hex screw standoffs) was stuck in the cable and that end of the cable was not held in tight and must have just barely been making a connection and that was causing the intermittent stepper problem.