OK, I received my printer today – probably the messiest ink jet printer I have ever layer my hands on!
A few things before I post the photos:
– the carriage is incredibly fast!
– the carriage contains an optical gate to count x positioning, and a reflective light sensor to sense ink head alignment
– the carriage has a PCB inside with two caps and an 8 pin unmarked chip
– the ribbon to the ink head has only 24 connections, and only 20 seem to be used. Many of them go to multiple pins on the head
– two traces are super wide, one is wide, the rest is hair-thin
– everything is soaked in ink
– HP is very smart: removing the scan unit gives full access to the print mechanics. The software recognizes the missing scanner, but still works as a printer. Wow!
– I did get it to print after cleaning and fixing the car wash. Now my hands are black, and the printer is white again 😉
So next I need to solder 24 wires that withstand the carriage acceleration onto the ribbon connector, reassemble the carrier, and then log the data arriving right at the print head. Fingers crossed.