HP DeskJet GT 5820 - Manual (Page 97)

4. Open the front door of the printer.
5. Open the printhead access door and wait for the print carriage to move to the center of the printer.
CAUTION: The instructions in the following steps apply only when you install printheads during initial
printer setup. If printheads have been primed with ink, you must not open the printhead latch. Opening
the latch can cause permanent damage to the printheads.
6. Push down to open the blue printhead latch.
7. Remove the printhead indicated in the error message.
8. Clean the printhead contacts and printer contacts.
ENWW Printhead issues 91