Questions & Answers
Odd vertical lines showing up
No, for be sure I removed the printer's belt, I started a dry print and I put 60cm of an other belt trough the gear of one of the two steppers, I held the two ends of the belt with a little force for accompany the move of the stepper end I've clearly felt the little jerks in my hands from the stepper, no smooth movement. And that's worst when the head do a curve! I've changed de voltage, the steppers, the drivers, 1/16 to 1/32... nothing works.
Have you already adjusted the current for the drivers? Motors need a certain amount of current to hold microsteps. If you say jerks on a move I assume a low move does more hop-hop-hop between full steps making it not smooth. That is clearly not that visible in your picture. Problem with more current is that drivers get hot and might need cooling to not tuen off from overheating. Also motors should be able to stand set current. They also get hot but would say 40-50°C is not uncommon here. If all are cold you are not working where you need to be.
I use tmc2100 with cfg1 mode for more quiet, I tried all voltage between motors no move and drivers over heat (0.35v to 1.1v) and the verticals lines was every time there with no visible difference with the different voltage. I tried the same thing with drv8825 and no difference too. I will try with TL-smoother on x & y but I don't relay believe on it. I'm afraid I have to try with and other motherboard like rumba or something, more expansive and perhaps useless test
Maybe first do a very simple test. Put some tape on a motor shaft and move step wise and see if they differ in rotation. You have no force here so it should be possible to position each micro step. Even better visible is maybe a clamp as it is stiff and shows better the moves.