Hp designjet 500 black printhead is still showing in carriage although i already removed it.

[BURNZZZ]

C7769B

Hello. I have a question regarding Hp designjet 500. It shows black printhead is faulty with X mark.   When i try  to replace it with new printhead expiring 2021, its still showing faulty printhead with X mark showing in the carriage. When i try to remove it, its suppose to show empty and blinking printhead "missing", its still showing replace printhead. The plotter seems to remember the old printhead even though I have replaced it with new one.

I have upgraded to latest firmware...dowgraded to previous firmware...upgraded it again, but all with same results.

Now, I have tried to prime the tubes and when it ask me to remove normal printhead, it still remembers the faulty printhead inserted and still asking to remove it.

Any help would be so much appreciated. Thank you

[Repairatrooper]

Make sure that the contacts in the carriage are clean. If you see ink you need to unplug the printer with the carriage in this position then use cotton swabs moistened with water to clean all ink off the contacts. Let it dry before inserting the printhead, locking it down and then reconnecting the power.

[BURNZZZ]

i have aleady changed the trailing cable and carriage assmebly. its the same issue. the black printhead is still marked as X although i have removed the printhead already

anybody knows how to harde reset or something

any help would be very much appreciated