km c200 p21 error code

[rprem]

yesterday i have installed one c200 after i switched on the machine it works good then i started the installation procedure it gives error code p 21 and i cant make gradiation
adjustment i had cleaned idc sensor checked drum hvps also any ideas?

[Stirton.M]

P-21: Color regist test pattern failure

Relevant parts
Black PC drive main sensor (PS16)
Black PC drive sub sensor (PS18)
Main drive unit
Printer control board (PRCB)

Step Action
1 Perform the faulty sensor check procedure. *1
2 Check the sensor, for which a faulty condition has been checked, for installed position and
proper connector connection.
3 Wipe the sensor, for which a faulty condition has been checked, clean of dirt if any.
4 If P-12 persists, change the main drive unit.
5 Change PRCB.

Relevant parts
Transfer belt unit
PH unit
Printer control board (PRCB)

Step Action
1 Check the flat cable for proper connection and correct as necessary.
2 Wipe clean the surface of the transfer belt with a soft cloth, if it is dirty.
3 Change the image transfer belt unit if the transfer belt is damaged.
4 Change the PH unit.
5 Change PRCB.