Canon Multipass C20/C3000

[Brian]

My C20's paper feed roller stops 180 degrees out of sync and no longer feeds
properly. It takes through 3 sheets without printing and then stops with a
sheet half way through.
This happened once before and the repair shop took about 10 minutes to fix
it. The repair shop has closed down and Canon cannot/will not help. There
are no other repair shops in my area.
I guess that it's a simple job but I can't see how to do it myself.
Can anyone offer any suggestions?

Thanks,

Brian

 

[Brian]

My C20's paper feed roller stops 180 degrees out of sync and no longer feeds
properly. It takes through 3 sheets without printing and then stops with a
sheet half way through.

I'm not explaining this too well.
It is characterised by the fact that the paper tray is raised in the idle
state (whereas it should be down) and the flat on the feed roller is facing
forward.