LCD Flickers when powered off and moving cheapskates

[Russ]

So i'm working on the Max V2 hotend, power is switch off, and I moved the cheapskates so that they are inverted. I noticed the LCD will flicker blue like power is being briefly applied to the Rambo. This was unexpected.

Is it supposed to do this? Could I have wired something wrong? I can imagine that the stepper is acting like a generator, feeding current back into the powered-off Rambo, but could this damage the board? I can't imagine it's good for it. Perhaps I just need to move the cheapskates very slowly so not to generate as much current. Or do I need to unplug the steppers from the board before moving the cheapskates?

Just had to ask - very strange indeed!

Cheers,

[Eric]

That's exactly what is happening. The motors act as generators when external force is applied. So long as you don't force the cheapskates to move rapidly, you should be ok.

[Jimustanguitar]

Yeah, try not to do that if you can help it. That would toast another printer (the ATX power supply has a resistance even when it's off, so it helps dissipate that charge instead of cooking board components).

I've never seen a damaged controller from this personally, but warning abound.