This problem is kicking my butt and causing me to pull what little is left of my hair out! Machine has only 160k on it. Only, but always, jams on duplex. Happens from all drawers. Always stops at reg. and kicks down B2 gate. Many times the rear side of the paper is folded over. Seems like should be obvious problem but damned if I can figure out.
Tried whole different duplex unit with exact results. Pulled reg. section out under dev. unit. Cleaned all sensors, removed, ck'd and cleaned guide plates and mylars. The bottom mylar gets pushed behind top Mylar. Don't know if this is what's catching paper or is result of the jam. If running multiple duplex copies there are usually two or three sheets stuck there, at B2 gate.
Also checked gate and plates that guide paper into duplex unit for burrs, all seem ok. Gotta go back again tomorrow(today) and try again. Not sure what's next. Any ideas much appreciated as I have three impatient women expecting me to fix this #%*@ machine!!!