Shatle fult eroor - Tally Line Matrix T6050 Printer

This error indicates the print mechanism is not able to move, in the first instance check;

There is no paper jams etc whcih may cause an obstruction
Check the ribbon is correctly installed and is the correct side of the ribbon shield
Check the platen gap to ensure this is not trapping the ribbon / paper and preventing the mechanism moving.

If the above actions do not resolve the problem the next thing to check is the Shuttle Mechanism,
Check the drive belt is in place and does not slip
Clean the rear side of the shuttle weight wheels, the sensor looks at the rear of the balanced wheels.
Check the shuttle motor to ensure it is working
Check for damage to the shuttle drive gears.