trouble with carriage jams on HP 6950 printer

[riscco]

• HP officejet 6950 printer
  Paper jammed during printing. I pulled out the crumpled paper completely through the output tray. There was not any jammed piece of paper left in the printer, I checked everything thoroughly, the ink carriage moves easily, nothing prevents it from moving, it also moves freely when the printer is turned off by hand. Since then, after properly turning off the printer with the power switch and turning it on, it still gives me an error message that it was not turned off properly and I should use the power switch to turn it off. Whether I acknowledge this error message or not, another carriage jam warning appears - even though everything is fine, no paper left, nothing obstructing the tray carriage - I open the printer so the carriage is in the far left position and not on the right, at the same time does not move to the middle part (e.g. as when changing cartridges) but goes from left to right three times and parks again on the far left. Then the carriage jam error message appears again and every time I confirm it, the carriage again goes from left to right three times and stays on the left. I can't run print diagnostics and print nothing. I also tried a factory reset, selected and checked the cartridges, etc. but nothing helped. Does anyone know what could have gone wrong and a solution? Thanks for any advice.

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