CS 520i with DF720B jamming! ( J81)

[CompyTech]

We have one of these dreadful built-in finishers jamming on finishing functions with code J81. The paper basically stops in the conveyance unit just at the decurl rollers. Nothing spins in there. We have checked everything from sensors, rollers, to solenoids. We(think) have it narrowed down to the roller motor and the FNS main PWB. Anyone dealt with these dreadful contraptions before, have anymore ideas?

Thanks

[blackcat4866]

I do have one of these internal finishers, but I tracked my J81 and J51 jams back to the duplex and pre-registration clutches. Mainly it jammed first thing in the morning. Does this sound vaguely familiar? =^..^=

[CompyTech]

I do have one of these internal finishers, but I tracked my J81 and J51 jams back to the duplex and pre-registration clutches. Mainly it jammed first thing in the morning. Does this sound vaguely familiar? =^..^=

Actually, it will duplex ok. When you try to staple it will jam. Then when you try to duplex after that it will jam untiill you reboot the machine. As far as I can tell the duplex paper path doesn't really factor into the finisher. But that gate will close off in there to allow entry to the finisher.

[blackcat4866]

I've spent a good bit of time with that gate, but never really found anything promising, excepting a peeled off address label that was fairly obvious. Good Luck. =^..^=

[CompyTech]

Thanks. I'll find out soon when we get the parts. This has been in our shop for a while. So it has been one of our summer projects.

[blackcat4866]

My problem child resurfaced this week. To my personal gratification it actually jammed several times consecutively ... enough that I could finally properly diagnose it. It came down to the one-way gear Z32S driving the last de-curl roller in the JS-720. I cleaned and lubricated the one-way bearing and it immediately ran 300 (100 stapled sets of three originals).

Want a theory? The de-curl/heat sink roller absorbs heat from the prints and the fuser, warming the one-way bearing, and evaporating off the lubricant.

It's very easy to access, only removing the upper cover. The job separator can remain installed. So I'll be checking these more often. (303MA16140 Gear Z32S OW) =^..^=