Need Help with my 82905 Printer - IL Version

[Michael Fehlhammer]

My recently purchased 82905 impact printer ( the rare HP-IL version ) obviously doesn't have a mechanical problem: the self test printout is fine.
But it ignores any print jobs from the calculators!
There is no error on the IL loop ( like timeout ); DEVID$ correctly shows "HP82905B". So I assume the IL interface is intact, but the connection to the print mechanism is broken !? Did anyone encouter a similar problem any time?
To me it seems this is a rare defect, but I don't understand much about electronics.
What could I do, is there a chance to fix that?
Or does anyone offer a repair service? It would be so sad if I had to trash it.