B363 J99-01

[Brett GS]

Hi all
Pulling my hair out.
Got a B363 with jam code J99-01 only from tray 1.
Machine has 750000 clicks, so far changed complete feed unit, registration unit,main drive,both motors,casset drive unit,complete tray 1,fuser,exit unit,pcrb and complete side door.
Firmware is up to date.
Paper reaches the fuser and stops and throws the jam code. From tray 2 and bypass all feeds fine.
What am i missing??

[tsbservice]

This is what troubleshooting guide recommends:
1. Check and clean Document CD size sensor (VR1), and Document reading motor (M1) and Document feed motor (M2).
2. Try lowering the registration loop to a negative number [Default = 0].
3. If code continues, replace the PRCB.
4. If code is still present, replace the MFPB.

[Synthohol]

Two things come to mind number one the feed unit that you replaced did it happen to come from a 423 if it did the wiring is different because there is an extra sensor in a 423 feed unit slower models do not have this number two the registration roller under the drum make sure that the bushings are allowing it to spin freely and not binding up those are the only two things that I have seen that cause that code that are just physical good luck