It is time to toss it. I had a deskjet 3820 that does the same thing.
When connected to a computer, the computer monitor displays "Mechanism
Error. Please call for service". The printer flashes the resume light.
Pushing its resume button does nothing other than make the printer
flash an error sequence. The problem is the unit has lost its ability
to communicate with the cradle motor and can't move the cradle out of
the storage area on the right.