P-21 error in KM Bizhub C451 and registration not proper

[janinaresh]

Thanks in advance
I have a Konica Minolta Bizhub C451, which i face error is P-21 and registration out, I change PH Unit, Transfer Belt Unit and Magenta Imaging Unit but problem not solved, I attached herewith a demo copy of Print, Please guide how to solve this problem.P_21_Error.jpg

[copyman]

Did you clean the IDC sensors? Could be the PRCB board but very unlikely. I've even had bad image units cause this issue. Don't think you can do Gradation adjustment as long as P codes are displayed, but once you get rid of P codes you need to do Stabilization & Gradation adjustment

[tsbservice]

On this model you may need to replace both IDC Registration sensors.

[Synthohol]

or do a LPH skew reset.
its in service mode.
sometimes it helps a lot.
then maybe a minor registration adj.
9/10 times i get lucky especially after cleaning the sensors under the belt.

[allan]

Don't think P21 is the only P-code. Check the warning history for P31 or P33.
The Key color encoder is not working ok.
If none of the other solutions work then replace the drum drive unit.

[copyman]

Again the big question the original poster needs to answer is if he cleaned the (2) sensors under transfer belt? Like syn posted 9 times out of 10 the P codes go away after cleaning sensors, if the transfer belt is good and clean of course. Then you will be able to do gradation adj which will sync all the color together. Actually it may look good after cleaning those sensors but do grad adj anyway.

Keep in mind even if a low meter the C451 is still an old machine and could be many things. Was a decent machine for it's time. A lot of bulletins / mods! but really only a few serious flaws, few that come to mind, fuser noise, black dev leaking, tray 3 jamming like Bob Marley!

[copier tech]

Thanks in advance
I have a Konica Minolta Bizhub C451, which i face error is P-21 and registration out, I change PH Unit, Transfer Belt Unit and Magenta Imaging Unit but problem not solved, I attached herewith a demo copy of Print, Please guide how to solve this problem.P_21_Error.jpg

Did you fit a NEW transfer unit or a USED one?

[allan]

Don't think P21 is the only P-code. Check the warning history for P31 or P33.
The Key color encoder is not working ok.
If none of the other solutions work then replace the drum drive unit.

Ok took more time to check the image and read the post...
K, Y and C are more or less aligned.
So not a faulty encoder i would guess, but still check the warning history.
Strange that its only M that is out.

So would not like to think its the transfer belt but could be.
Under level history the IDS values of the two sensors should match. If they don't then yes one of the 2 IDS sensors or the transfer belt.
Also do half-tone prints to check if the entire page gets developed and transferred, but then you should get a P-code for the faulty color.

[janinaresh]

Did you clean the IDC sensors? Could be the PRCB board but very unlikely. I've even had bad image units cause this issue. Don't think you can do Gradation adjustment as long as P codes are displayed, but once you get rid of P codes you need to do Stabilization & Gradation adjustment

I clean the idc sensor

[janinaresh]

Did you fit a NEW transfer unit or a USED one?

Used one which is not error in other machine