Epson TM-U950 Technical Manual page 133

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