hp officejet pro 8720 printhead appears to be missing

Could it really be the problem? Is it still worth a try to buy new original HP cartridges and will it even fix the problem? Or is the damage done already and not reversable? I’m a bit hesitant to invest more on this printer since I already blew up 72 EUR for the printhead…. One last thing that I came by today on this page is that it might be the unoriginal ink that I installed for the first time last time I replaced my cartridges (about 3 months ago, I switched the last color from original HP to unoriginal). I don’t have the equipment or knowledge to test if the cables actually work, but everything looks ok. I’ve reset the CMOS battery on the main board, disconnected all cables and checked the cables specificly for the printhead carriage. (This one is also possible to buy on aliexpress, but I’ve not done it).

I disassembled it and cleaned the contacts on the PC board. Since the new printhead failed I thought maybe the problem is in the printhead carriage inside the printer. Then I continued to troubleshoot some more. I then went on to buy this new print head from eBay, but the new one instantly gave the same error message. I ordered this cleaning solution and cleaned the printhead, both soaking in the solution for some time and pushing the solution through.

I’ve disassembled the printhead and cleaned the contacts on PC board. I reseated the printhead one time and the printer worked until next day, when the same error appeared. One day out of the blue, I recieved this error message: “The printhead appears to be missing, not detected, or incorrectly installed. I bought the HP OfficeJet Pro 8620 printer in 2015 and up until december 2019 it has worked perfectly. I’ve read through most of the other threads on the internet about this problem, but I’m still creating this one both for documentation purposes, and in case someone has a solution that I’ve not thought of! Text in bold are considered important for the troubleshooting.

Hp officejet pro 8720 printhead appears to be missing