Bizhub C308 weird color registration/ print head problem

[SAR]

Any color copies /prints come out with black lines all over them with color registration way off. Black and white copies and prints are fine.
Copier had some P-21 and P-28 warning codes. Transfer belt has been replaced and IDC sensors cleaned. Tried to run Gradation, but Stabilizer comes up NG.
Have tried Initialize/ Image Stabilization, Print head skew reset. All consumables are in good shape.
I'm thinking it's a bad print head, but wanted to see if anyone here has seen this.IMG_1979.jpgIMG_1980 (2).jpg

[srvctec]

I'd re-secure all plugs on the MFPB and PRCB as well as re-seat memory and NVRAM. Also maybe re-secure plugs to AIDC board assy as well. If you have another machine to take parts off of, take the AIDC board assy and swap it to see if there is a change. If no change then I'd say PH unit from the looks of it.

[docdot69]

If You wanted to save money, and put drum k with color chip, thats the result, because KM is smart, and they changed a little drums K, to avoid putting them into colors place. Just try to swap with old color drums, or if you have other machine, swap drums between them. Just to try.

[tsbservice]

The only common parts between P-21 and P-28 malfunction codes are transfer belt unit and IDC sensor shutter solenoid SD2.
Since TBU is new I will concentrate on SD2. I will also check both IDCS sensors values in service mode for abnormal values.
Can you see how color patches are formed on belt?

[tech51]

Had something similar to your magenta print, except mine faded out to the rear. That was the print head.

I’ve also had to replace a further two print heads because the cyan was completely missing!

[SAR]

Thank you for the replies! I replaced the print head in the copier and it fixed the problem.

[bitels85]

Thank you for the replies! I replaced the print head in the copier and it fixed the problem.

Hi, I recently have excatly the same problem in Develop ineo +308 copier
I took out laser unit and cleaned it. I was extremely careful, so I'm pretty sure I didn't damage it in anyway.
After that, printing quality became perfect, but only for one day

Before replacing laser unit I will try reconnect all plugs on MFPB, apply latest FW, and perform initial troubleshooting procedure and engine troubleshooting procedure.

Somehow, I'm not convinced that laser is broken...

[WLIT]

I have fixed numerous C308 machines by removing the guide plate above registration where the IDC sensors are located and cut the tie wraps to the sensors and the rest of the harness. The wire harness goes to the front PCB behind the waste toner container so the front inner covers need to be removed. If you want to you can check the reading of the IDC sensors in Service mode> State confirmation> Level history 1. If your machine is in a warning with the oil can showing in the top left corner when you enter Service mode, the values of the IDC sensors will be off or may not even show. Think they should each be around 3 volts when normal.

[bitels85]

I just remembered that this particular copier had this problem before in 2019. I found demo page in my documents (attachment). Problem was solved without replacement any of parts. Hope this time will be the same way. I'll let you know soon.

[jotunn]

Take apart PH Unit and gently clean up polygon mirror, and SOS sensor. PH Unit is not hermetically sealed, so polygon grabs a lot of dust, and C308 is surprisingly sensitive to this problem.