New printhead does not initialize on DesignJet Z6

[TWilson1]

I have an HP DesignJet Z6 44-in PostScript Printer, purchased in 2018.  In February 2023 there was a dashboard message to replace a printhead.  I had three in stock.  I ended up trying all three, and each time the printer starts to initialize for a few seconds, then goes back to the “replace printhead” message.  Even though they were not out of date, I purchased three new printheads.  Same thing happened. These are all HP brand printheads. I have installed the latest firmware package from the HP website. I have cleaned the contacts. I have soft-booted and hard-booted the printer with printheads both in and out of it.  Still in the same loop of replace message—no initialization—replace message again.

I have searched on the internet for many weeks now, and although I have seen similar complaints, I have not found a solution yet. I would appreciate any advice.

[Repairatrooper]

There have been cases where the left spittoon gets polluted with ink which prevents the printhead from ejecting all the shipping fluid. Open the main window and look at the left foams. If there is visible ink built up you can  use a cotton swap to remove the excess ink. Then update the firmware which contains a fix for this issue and you should then be able to install a new printhead successfully.