4-20
Troubleshooting
Rev. A
Cutter blade operates
but full cut is not
performed or becomes
error.
Output signal failure
B
Check output signals at
contact pin holder sub
assembly with an
oscilloscope (blue: F/P
position pulse; red: reset
pulse; black: common).
Replace contact pin
holder sub assembly and
cutter slider assembly if
irregular chattering
(more than 2 ms pulse
width) is generated.
Remove any
contamination on
cutter slider assembly.
Paper dust or other
contamination has
accumulated on cutter
blade.
B
Check for paper dust or
other contamination
Remove cover-cutter
blade receiving
assembly and remove
paper dust or other
contamination.
Cutter blade operates
but full cut is not
performed or becomes
error.
Gear wheel wear or
damage
B
Check gear wheels for
wear and damage.
Replace gear wheels as
required.
Paper roll supplying
problem
A
Check whether paper
roll corresponds to
specifications.
Use paper roll that
corresponds to
specifications.
A
Check paper feed path.
Repair paper feed
mechanism as required.
Slip paper is positioned
correctly, but printer
does not detect it.
Detector-slip paper
insertion sub assembly
failure
B
Insert paper and check
detector output signal
with an oscilloscope.
Replace detector-slip
paper insertion sub
assembly.
Slip paper problem
A
Check whether slip
paper corresponds to
specifications.
Use slip paper that
corresponds to
specifications.
EEPROM (U20) failure
B
Check EEPROM (U20)
output signal.
Replace EEPROM (U20).
Slip paper eject waiting
status is not released
when slip paper is
removed.
Detector-slip paper
ejection sub assembly
failure
B
Check detection signal
by using an oscilloscope
when slip paper is
removed.
Replace detector-slip
paper ejection sub
assembly.
Slip paper eject
detection circuit failure
B
Check pin 70 of CPU
(U12) with an
oscilloscope.
Replace detector-slip
paper ejection
assembly.
Paper roll near-end
detection does not work
properly.
Microswitch failure
A
Check continuity
between microswitch
terminals and check on/
off operation.
Replace microswitch.
Slip paper is not
released.
Internal diameter of
paper roll core is too
small.
A
Check internal diameter
of paper roll core.
Nominal value: 10 mm
(.39”) or more
Use paper roll that
corresponds to
specifications.
Table 4-3. Printer Mechanism Problems (continued)
Problem
Probable
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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