out of box blank image black only mp c4503

[wyo19]

Brand new C4503 set up in shop worked PRO-CON 11111111 at setup. Delivered Machine no black at all only code SC 492 and PRO-CON 11111159. Tried PCDU in another machine works, I'm lucky to have a another machine(Brand new,but crushed) to pull parts and boards off of. These are the parts I've swapped out with no change:
HVPS
TTSPS
CB PS
DC PS
ITB
PTR
PCDU
IMAGE BCU
K MOTOR PCU AND DEVELOPER
BCU
I Have narrowed it down to no "DEVELOPER BIAS" hence no image, now am at a crossroad as to what is causing it,maybe a harness or something to do with the connectors (2) that the pcdu contact when sliding.
Any Help or direction would be appreciated...
I will be trying a couple of things on Sunday Firmware, NVRAM clear.

[Tonerbomb]

Stay away from the NV ram clear, firmware is always a good thing to update, but probably not the issue. I would really look at the PCDU and the connections and end plates for this first. Did you try the PCDU from the donor machine?? If so did it do the same thing??

[wyo19]

Stay away from the NV ram clear, firmware is always a good thing to update, but probably not the issue. I would really look at the PCDU and the connections and end plates for this first. Did you try the PCDU from the donor machine?? If so did it do the same thing??

I upload all data then do a memory clear,since the machines never been in service. Don't need to backup address book.
I used the PCDU from the "crazie" machine in a working machine, no problem. I think it could be the little spring in the back of the copier,will know more tomorrow.

[copier tech]

If this is a brand new machine out of the box why don't you simply put in a DOA claim & save yourself the hassle!?

Being a new machine it could be any number of things.

[duct tape]

How about the black transfer roller in the it the itb unit I've seen different colors do that the roller can come unmounted.

[wyo19]

How about the black transfer roller in the it the itb unit I've seen different colors do that the roller can come unmounted.

I've tried swapping out with another ITB assembly, and there is no image on the drum

[Oze]

In that vast list of swapped parts I didn't notice laser?
Have you tried a different laser assy?
Could be that the black pcb has shat itself...sounds like the laser is not writing for black.
What happens if you try to do an ACC or run music?
Does it fail?
Does it throw a density code?
Questions questions questions lol.

[slot]

just had a brand new laser which we fitted to a mpc4503 and gave blank copies on black but ok on colour see my previouse post sc240-01 the fault was the new laser unit the very right mirror hidden under a cover had come out of position when we proded about with it the mirror slipped back in and copies were ok we didnt get any error code as the beam must of made the line detect sen

[wyo19]

One of the first parts I tried was a laser unit (gotta love parts machines) So I went over connectors one-by-one (fml) found the problem with the connector on the laser from the machine side was not seated all the way.... Thanks for all the replies....

[wyo19]

In that vast list of swapped parts I didn't notice laser?
Have you tried a different laser assy?
Could be that the black pcb has shat itself...sounds like the laser is not writing for black.
What happens if you try to do an ACC or run music?
Does it fail?
Does it throw a density code?
Questions questions questions lol.

ACC and music failed no code except for the only one it thru SC-492 which was not listed in my 01/01/15 manual,but was listed on my 03/15 strange... Totally threw me off in my search for the fix.. Thanks again for your post,it helped me find the fix...