Printronix P9012 Maintenance Manual page 81

All H's
All Underlines
All Black
Troubleshooting
A pattern of all uppercase letter H's useful for detecting missing
characters or dots, smeared characters, or improper phasing.
Ribbon
Hammer bank cover
MPU Sensor
Hammer spring
Hammer coil
An underline pattern useful for identifying hammer bank
misalignment.
Mechanism driver or MCU PCBA
Hammer back cover
Hammer tips
Paper feed motor or belt
Splined shaft bearings
Tractor bearings or belts
All dot positions are printed, creating a solid black band. Exercises
shuttle and hammer bank at maximum capacity.
Hammer coil
Hammer spring
Hammer bank cover
Power supply PCBA
Mechanism driver PCBA
4–15