Tube deck not coming all the way up

[mr.badwrench]

Tube deck suddenly doesn't come all the way up? Run it all the way down and look at the chain shown with red tape here. The chain should be tight. If it's loose as you see here the chain shown with the blue postit may have jumped a cog. It's less likely but possible that one of the sprockets on the shaft at the left side of the first pic may have broken its key and turned on the shaft. I didn't exactly reproduce the condition for the pics. I lowered the tube deck onto a couple of 2X4s laid edgewise.

[Bowler4Ever]

Are you hearing any abnormal sounds coming from the machine at all? Have you checked the sprockets on another machine to compare them to?

[mr.badwrench]

Are you hearing any abnormal sounds coming from the machine at all? Have you checked the sprockets on another machine to compare them to?

This happened years ago. I recreated it to show how it could happen and how to deal with it.