J1701 Duplex Bizhub 751

[MVPunisher]

So ... Stumped on this one. This code always seems to throw me around, but usually I get it.

Have a Bizhub 751 that is jamming 1701 jams on 2sided. Not all the time but very easy to duplicate. Much better luck with a 1 page job (still 2 sided)

Replaced both duplex clutches, removed the mylar under fuser turnover section, replaced duplex sensors, loop sensor, reg sensor, Manual feed gear and shaft in rear (attached to main body) also the manual feed gear attached to the bypass unit, also the ADU board. Still happening, it seems like it is stopping in the pre reg rollers that are driven by those manual feed gears on main body, not ADU.

So i guess my next step is to rip through the back of the machine and figure out whats going on back there, usually dont have to go that far, Any help is appreciated.

Thanks

[MVPunisher]

So I resolved this by doing 2 things.

1- (this may or may not have been neccesary) M6 was hesitating to drive the bypass gears (could run I/O 26 load check and see it struggle) I had already swapped entire bypass assembly so I know it wasnt in bypass, so I replaced M6.... upon replacing m6 it stopped sticking and stopped hesitating in the load check ... then -

2. I set the pre-registration timing under "machine" in serv mode to +10MS and that completely resolved the duplex 1701 jams.

yikes

[allan]

Strip open the ADU to get to the sensors and flags make sure they operate correctly. How many prints is on the machine? the fact that you need to set the machine so far out of adjustment means there is still something wrong.

That M6 motor should be good for the entire life of the machine never had one go bad.

[MVPunisher]

As for M6- I agree with you it should last, I have never had to replace one. However...it was covered in Developer from a prior developer mishap. So that could explain it. I already not only checked the flags, but i replaced the sensors themselves. I only went this far because I felt like I had to. Next step was PRCB but i thought ADU drive board controlled this timing (already replaced)

I literally could not get 5-10 pages out when I arrived this morning, the motor was visually hesitating. No hesitation now, and it ran 300 duplex-ed before I left and still hasn't jammed rest of the day. 2.5 million on machine. I agree something probably still isn't right but there isnt much left and I am not going to poke the bear til it comes back.