Radio Shack 26-1154A Service Manual page 39

Table
4-3.
Detailed Troubleshooting Chart
(cont'd)
TROUBLE
Carriage emits
thumping noise while
printing.
Excessive print den-
sity at beginning of
print line
(over-
print)
.
No ribbon movement.
PROBABLE CAUSE
Printer requires general
cleaning and lubrication.
Defective head-carriage
assembly.
Defective carriage molded
rack assembly.
Defective mechanism assem-
bly.
Defective printed circuit
board.
Defective ribbon drive
motor.
REMEDY
Clean and lubricate printer.
(See paragraph
4.6.)
Replace head-carriage
assembly.
(See paragraph
6.8.)
Replace carriage molded
rack assembly.
(See para-
graph
6.5.)
Replace mechanism assembly.
(See
paragraph
6.2.)
Replace printed circuit
board.
(See paragraph
6.3.)
Replace ribbon drive motor.
Defective printed circuit
board.
Replace printed circuit
board.
(See paragraph
6.3.)
4-9