4-12
Checkpoint
Check attaching position of the
solenoid.
Check tension of the belt.
(Nominal value: 40 g (.088 lb))
Check resistance of Paper
feed motor.
(Nominal value: 40
Ω
±
5%)
Check paper feed motor drive
terminal signal of CN12 with
an oscilloscope.
Check the gears for wear and
damage.
Check whether slip or valida-
tion paper corresponds to
specifications.
Check paper roll installation.
Check the right and left bal-
ances of the roller assemblies.
Check surfaces of the roller
assemblies for wear and for-
eign matter.
Check gears for wear and dam-
age.
Check paper feed motor drive
terminal signal of CN12 with
an oscilloscope.
Above six checks have been
passed.
Check continuity between
microswitch terminals, and
check on/off operation.
Check IC (U3) output.
Check DIP switch settings.
Check to see if the cable is
RS-232C null modem cable,
and check its continuity.
Action
Adjust the solenoid attach-
ing position as described
in
Main Assembly 7 in Sec-
tion 5.3.3.
Adjust the tension as de-
scribed in
Adjustment B in
Section 5.3.4.
Replace Paper feed mo-
tor.
Repair paper feed motor
drive signal generator cir-
cuit.
Replace any damaged
gears.
Use paper that corre-
sponds to specifications.
(See Section 1.2.3,
Paper
specifications.)
Install paper roll.
Replace S paper feed
roller assembly or V pa-
per feed roller assembly.
Replace or clean S paper
feed roller assembly and
V paper feed roller as-
sembly.
Replace any damaged
gears.
Repair paper feed motor
drive signal generator cir-
cuit.
Replace Paper feed motor.
R e p l a c e M i c r o s w i t c h
sub-assembly.
Replace IC (U3).
Set DIP switches correctly.
(See Section 1.3.5,
Switches and buttons.)
Replace cable.
Problem
Slip or validation paper
is not fed.
(continued)
Cut sheet feed pitch is
irregular, or paper does
not advance and print-
ing is all on the same
line.
Paper roll near-end de-
tection does not work
properly. (
✽
)
Different character than
input code is printed.
Level
A
A
B
B
B
A
A
B
B
B
B
B
A
B
A
A
Probable Cause
Poor adjustment of
Solenoid-Paper
holding switching
position
C feed belt tension is
loose.
Paper feed motor wire
break
Main circuit board unit
failure (Paper feed motor
drive signal failure)
Gear-Intermediate or In-
termediate gear B wear
Cut sheet problem
Paper roll is not installed.
Pressure balance of S pa-
per feed roller assem-
bly or V paper feed roller
assembly is not correct.
S paper feed roller as-
sembly or V paper feed
roller assembly is defec-
tive or contaminated.
Cut sheet feed driving
gears wear or damage
Main circuit board unit
failure (Paper feed motor
drive signal failure)
Paper feed motor failure
Microswitch failure
Main circuit board failure
(Receiver/driver IC failure)
Communication condition
such as transmission
speed not set correctly.
Communication cable fail-
ure
(
✽
) This applies only when near-end detection is selected (ESC c 4 command) in the application program.
Table 4-3. Printer Mechanism Problems
(continued)
CONFIDENTIAL
Summary of Contents for U375 - TM B/W Dot-matrix Printer
Page 2: ...Technical manual TM U375 U375P English 4005791 Copied Date 199 Copied by ...
Page 54: ...2 23 Figure 2 44 Host Interface Circuit and Custor Display Interface Circuit CONFIDENTIAL ...
Page 58: ...2 27 Figure 2 49 Carriage Motor Drive Signal Timing Chart CONFIDENTIAL ...
Page 149: ...6 2 Circuit 1 CONFIDENTIAL ...
Page 150: ...6 3 Circuit 2 CONFIDENTIAL ...
Page 151: ...6 4 Circuit 3 CONFIDENTIAL ...
Page 152: ...6 5 Circuit 4 CONFIDENTIAL ...
Page 153: ...6 6 Circuit 5 CONFIDENTIAL ...
Page 154: ...6 7 Circuit 6 CONFIDENTIAL ...
Page 156: ...6 9 CONFIDENTIAL ...
Page 157: ...6 10 CONFIDENTIAL ...
Page 158: ...6 11 CONFIDENTIAL ...
Page 159: ...6 12 CONFIDENTIAL ...
Page 168: ...7 9 Table 7 5 TM U375P Gate Array Pin Assignment continued CONFIDENTIAL ...
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