P9 error do not know

Replace the Black drum and developer unit (P9) (P16) and clean the IDC forward sensor(P5) (Requires removing the Transfer belt)
L4 Black Drum Rotation well passed its life.

You have a code that doesn't exist

http://errorcodeairconditioning.blogspot.com/2021/12/koppel-air-conditioner-error-codes.html

https://www.google.com/search?q=Koppel+Super+inverter+split+type+Air+Conditioner.+It+has+a+P9+error+code

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Error Code Definition: (Unit Size 36K - 42K) = IPM over temperature protection. Carrier AC Indoor Unit Displays Error Code: P9. Error Code Definition: (Unit Size 18K - 24K - 30K) = NA. Error Code Definition: (Unit Size 36K - 42K) = Open Contactor.
https://removeandreplace.com/2017/08/11/carrier-split-system-air-conditioner-error-codes-and-troubleshooting/

https://www.youtube.com/watch?v=M-fLGOYL84Y

reset network.

check The Transfer Belt or it can be the Black Image Unit . (P9 & P21 normally: black Imaging unit) but P21 can also be refered to Transfer Belt). ..

Sir, You have a registration error , which will require removable of the transfer belt and cleaning of the sensors below the transfer belt, recommended a tech do it, unless you know what your doing

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/normanj_7893313f0751935f

This might help. CLICK HERE to see an ATX power supply pinout.

hi piz Error code P9 and P21 appears on screen and when printing or photocopying using color black, blank copies are outputed

Unfortunately, I do not know P9 and P7. Can you tell me if they are multiple colored wires going into a header/connector? If they are single wires or thin wires you may be able to look at your header of wires which connect the pwr button, rst switch, power led, speaker ( 4 pin thin connector ) if p9 and p7 came off here they could be your power switch.