Extruder tensioner doesn't tension
I recently put a hardened nozzle into my 5th tool head, which hadn't previously seen much use but now I'm printing a lot of glass-filled ABS so using that extruder a lot. I've had multiple failed prints now where it just stopped extruding; I thought maybe it clogged, and each time there was a flat spot ground in the filament by the extruder gear wheel, but merely unloading, clipping the filament above the flat spot, and reloading it sufficed to get it working again each time, no cold pulls or needling the nozzle required.
Today I popped the tensioner lever and noticed that it was way too loose. The mechanism which applies tension to push the filament against the extruder gear wheel is bottomed out (while filament is installed) on this tool head, so the springs aren't even able to apply any tension. The release lever flips up with little resistance. Since this is applying very little tension to press the filament against the extruder gear wheel, I'm not surprised that it would start slipping and then get stuck as the teeth grind a relief into the filament. It's not obvious to me from looking at it what's wrong with this particular tensioner where it's bottoming out, while the tensioners on the other 4 tools aren't...
Photo shows tool 4 (tensions OK) on the left and tool 5 (loose tensioner) on the right.
(Click the image to see the whole thing, it's oddly cropped in the preview)
