4-14
Troubleshooting
Rev. A
Motor-carriage does
not operate at all when
power is turned on and
becomes error.
Carriage motor drive
signal failure
B
Check motor drive signal
at connector with an
oscilloscope.
Repair motor drive signal
generator circuit.
Wire break or bad
solder point between
connector and carriage
motor terminals.
B
Check continuity
between respective
terminals.
Replace wiring board
assembly.
B
Check solder condition.
Resolder as required.
Motor carriage
defective
B
Above three checks
have been passed.
Replace motor-carriage.
Detector-carriage sub
assembly failure
B
Move the carriage-head
and check the
detection signal by using
an oscilloscope.
Replace detector-
carriage subassembly.
Table 4-2. Printing Quality Problems
Problem
Probable Cause
Level
Checkpoint
Action
All dots do not print, or
print is very faint.
FPC is disconnected.
A
Check FPC connector.
Insert FPC again.
Wire break or bad
solder point in common
wire inside print head.
A
Check common wire for
continuity.
Replace print head unit.
Wire break or bad
solder somewhere on
the line between print
head unit and
connector.
B
Check common wire for
continuity.
Resolder parts or replace
wire break parts.
Platen gap is not
adjusted correctly.
A
Check platen gap.
Nominal value:
0.50(±)0.05 mm
(.020(±).0020”)
Adjust the gap as
described in the
adjustment section in
Chapter 5.
Input pulse irregularity
B
Check dot wire input
pulse with an
oscilloscope.
Repair input pulse
control circuit or input
pulse drive circuit.
A certain dot does not
print.
FPC wire break
B
Check FPC for
continuity.
Replace print head unit.
Wire break between
soldered point of flat
cable on wiring board
and connector
terminals.
B
Check wire between
terminals for continuity.
Replace wiring board
assembly.
Print head coil wire
break
B
Check coil resistance
with a multimeter.
Replace print head unit.
Bad solder point
between connector and
head coil.
B
Check wire between
terminals for continuity.
Resolder.
Print head wire break
B
Check for dot wire
break.
Replace print head unit.
Table 4-1. Initialization Problems (continued)
Problem
Probable Cause
Level
Checkpoint
Action
CONFIDENTIAL
Summary of Contents for TM-U950P - B/W Dot-matrix Printer
Page 2: ...Technical manual TM U950 TM U950P English 4005789 Copied Date 199 Copied by ...
Page 3: ...EPSON SEIKO EPSON CORPORATION Printed in Japan E96010130 0000SE CONFIDENTIAL ...
Page 8: ...iv Rev A Revision Sheet Revision Page Altered Item and Contents Rev A CONFIDENTIAL ...
Page 13: ...1 2 Features and General Specifications Rev A Figure 1 1 TM U950 Appearance CONFIDENTIAL ...
Page 119: ...4 6 Troubleshooting Rev A CONFIDENTIAL ...
Page 121: ...4 8 Troubleshooting Rev A CONFIDENTIAL ...
Page 124: ...Rev A Troubleshooting 4 11 TM U950 U950P Technical Manual End End CONFIDENTIAL ...
Page 138: ...Rev A Troubleshooting 4 25 TM U950 U950P Technical Manual Action 1 Action 3 CONFIDENTIAL ...
Page 226: ...6 2 Appendix Rev A Circuit 1 CONFIDENTIAL ...
Page 227: ...Rev A Appendix 6 3 TM U950 U950P Technical Manual Circuit 2 CONFIDENTIAL ...
Page 228: ...6 4 Appendix Rev A Circuit 3 CONFIDENTIAL ...
Page 229: ...Rev A Appendix 6 5 TM U950 U950P Technical Manual Circuit 4 CONFIDENTIAL ...
Page 230: ...6 6 Appendix Rev A Circuit 4 Circuit 5 CONFIDENTIAL ...
Page 231: ...Rev A Appendix 6 7 TM U950 U950P Technical Manual Circuit 6 Circuit 7 CONFIDENTIAL ...
Page 232: ...6 8 Appendix Rev A Circuit 8 CONFIDENTIAL ...
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Page 242: ...TM U950 U950P Technical Manual Printers Without a MICR Reader 3 4 Appendix 6 18 CONFIDENTIAL ...
Page 245: ...TM U950 U950P Technical Manual Printers With a MICR Reader 1 5 Appendix 6 21 CONFIDENTIAL ...
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