Here is a video of my lift. I have no idea what is going on right now. Before it was working perfectly but now it not working at all. Is it because of the motor or does it need another motor. Or is it because of the gear ratio? Any info will be helpful.
Compared to my original, you are using an 18 tooth (?) sprocket as the drive. If in addition to this you have friction on the linear slides (setup needs attention and careful spacing ) then two motors will probably (well certainly) not be enough power. Check for friction first, the lift sections should slide freely without the chain installed.
Have you removed the motors to check they are working ok?
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