Intermittent low power on all steppers

This is the week of misc. problems for me it seems.

Normally my LR does great and can push my arm pretty well on X and Y probably pushing a couple lbs of force but occasionally like 1/10 times its an absolute dog that can barely push itself around and skips steps all over the place.

I’ve got TMC 2209’s in an SKR 1.3 board with a 6amp PS powering the board, a buck converter, pi3, and 2 fans.

Here’s what I’ve done to troubleshoot so far with no luck. Eventually it starts working again like nothing ever happened but I cant figure out what has changed. I’m assuming it has to be power or temp but I cant find a smoking gun.

  1. Checked grubs not them, def skipping steps.
  2. Confirmed Stealth Chop Is Off
  3. Lowered speed
  4. Lowered Accel (This helps a bit but not enough)
  5. Checked for overheating (protection not tripped) but chips are on the hot side at 130C; Motors are fine and only warm to touch,
  6. Ran TMC diags all looks ok
  7. Made sure stealth chop was off.
  8. Upped Current (900 is useless, 1100 runs with some skipping, 1300 runs great but everything gets hot.)

I’m kind of at a loss. Next step is to order a bigger power supply and see if I’m just running short on current.

Swapped out the power supply with a 10Amp no improvement.

The board is getting 12.2v

Checked the voltages at the driver pots 1.2 - 1.3 v.

Detached buck converter and pi. Hooked back up and still no joy in fact it seems worse. Skipping steps just trying to move itself.

This is across all motors.

The config hasn’t changed since it was running good.

Not sure where to go next… the fact that it happens across all drivers suggests that it’s either a power issue, a board issue, or a config issue.

Anybody?

Well I’m confused I reflashed the board with my backup bin and it’s back to normal. No idea what’s changed.

Glad it is working again. From a “forensic investigation” point of view, is there any chance an errant gcode command changed the digipot settings?

It looks that way though for the life of me I can’t figure out what.

I have a macro that sets speed, acceleration, current, and sensorless endstop sensitivity. Then saves it to eprom via M500.

Since recovering I reran that macro and it’s still working fine.

Maybe I set something manually by accident then ran my macro which would have saved it.

I’ve added a M502 to my macro to load from default settings before customizing then a M500 to save after I’ve customized. Hopefully that will load a known good state each time.