Significant resistence on left arm

[Elysio]

Hi.

Today I had a standard cleaning and parts cheking time.
There I realized that the left arm has a significant resistence on some areas when I moved the arm up and down.
What can be the reason ?
The belt is tight as the other 2 belts, there is no difference.
What can it be ?

- Ball bearings of the belt transmission
- The steppermotor
- The steppermotor ball bearings
- The Rambo board ?

What di you think, should I order a neew steppermotor?

[Eric]

I assume you're talking power-off, but you can completely eliminate the Rambo board simply by unplugging the motor and seeing if there's still a problem.

Belt damage? Stripped belt debris binding in the gear? Visual examination during movement should reveal that. Check for gear slippage on shaft while you're watching.

If it were motor bearings, you should have a pattern of resistance every motor revolution. If so, remove the belt and see if you can feel it when you turn it by hand. If not, it's probably not a motor issue.

Arm joint(s) binding? Depending on how much force "significant" is. Can disconnect arms from carriage to eliminate as a factor.

Carriage issues? Wheels out of round/damaged? Probably a pattern of resistance, if this is the cause. Can test carriage by itself if you disconnect from belt.

Basically, eliminate causes until you narrow it down.

[Windshadow]

rapid movement of the cheapskates can cause the steppers to back feed current into the electronics when the machine is off or even unplugged.

I understand that they act as generators. I would not want to move the skates through their full hight distance in less than say 1 second, just to be on the safe side... or as above unplug them from the rambo board

[teoman]

What year of printer? Do you have the metal u-joints?