Need help repairing a hp9120 printer

[Roland57]

Hi,

Meanwhile I was successful to get my 9120 working:

The paper advance roll has been replaced with a silicone tube with 14mm/18mm inner/outer diameter which works perfect.

The old printhead showed mechanical problems and the flat-band cable had severe corrosion and a few interrupted lines: both have been removed.

For the printhead I used 0.35 mm enameled wire. With scotch-tape I fixed 7 wires in parallel like this:

[attachment=6671]

On the print-side (right) the insulation at the 7 tips has to be removed with some adhesives and the 7 pins have to be spaced equally over a span of approx 4 mm. This fits perfectly into the original fixture. To increase the pressure of the soft wires on the paper they must be supported by some tape:

[attachment=6672]

The 7 pins have to be connected directly to the circuit board, leaving the rest of the old flat cable untouched (maybe for a more professional repair in the future).
The results look promising:

[attachment=6673]

AT least for demonstration purposes the printer is in working condition !

Roland