P-28 C451

**Gaffers01** · 10-23-2012

I have a problem with a C451 that when customer copies anything green it comes out magenta,

The machine has a P-28 code so I am unable to run graduation adjustments.
I have printed the C M Y K test patterns and all come out fine.

I'm hoping that if I can reset this P-28 warning code then i'll be able run the graduation adjustment for copying and it will be okay.

I have ordered up the sensors beneath the Transfer belt, but if anyone has had a similar thing could you let me know.

**EarthKmTech** · 10-23-2012

remind me what P-28 error is, and I may have some advice.

**Gaffers01** · 10-23-2012

This is what the manual says, all iu's and transfer belt look fine.

P-5
IDC sensor (front) failure
•
When adjusting the IDC sensor, output voltage
detected for all eight sample patterns are 4.3 V or
P-28
IDC sensor (rear) failure
more.
•
When adjustment is complete, sensor’s output voltage
with selected light intensity is 1.0 V or under.
•
During image stabilization (gamma correction control),
detected output value for IDC sensor did not go below
threshold (half the value of what is detected by IDC
sensor on the belt surface) for three consecutive times
(position of the pattern end is not detected).
•
During image stabilization (gamma correction control),
sensor’s output value of each color for hyper 0 grada-
tion after the primary approximation is half the detec-
tion level on the belt surface or under

**907tec** · 10-23-2012

Which exact test patterns are you using? I would be curious to see the gradation patterns for each IU on 11x17 as well as the color sample pattern.

**Albonline** · 10-23-2012

do reset and stabileize and try a copy. if this helps the issue, then you are having a gradation problem, witch will require you to fix the idc sensors and run gradation.

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**EarthKmTech** · 10-23-2012

C451 series have a common issue with the HV2 board not providing belt cleaning bias.

You know when you have this issue because even with a new belt it just wont complete a stabilisation, usually due to a p-21 code which is generated because the stabilization pattern cannot be cleaned off the belt in a timely fashion and cannot be read properly the second and subsequent time round. Usually associated with this is transferal of smudgy remains of stabilization marks onto the firist few prints after an attempted stabilization.

I've never ever had the IDC sensors fail even though i carry them in stock they have never been the cause of any issue in my experience (except when dirty)

Ensure the IDC sensors are clean (and always clean them when you remove/replace a transfer belt for any reason, not doing so is a poor practice)