Handling, Maintenance, and Repair 2-11
3. Does not print
all dots.
The motor ro-
tates normally
but the printer
does noto print.
(1) Disconnection or
burnt-out of Cable,
head common line.
B
●
Check continuity be-
tween the Cable,
head common lines.
●
If no continuity ex-
ists, replace the print
head unit.
(2) Poor contact of the
Cable, head com-
mon line with
board ass’y.
A
●
Check continuity for
the soldered section
of the board ass’y
and Cable, head and
the soldered section.
●
When no continuity
is checked, re-solder.
4. Continuous
missing dots
Certain head
does not print.
(does not print in
several columns)
(1) Disconnection or
burnt-out of Cable,
head.
B
●
Check continuity be-
tween patterns of the
pertinent Cable,
head.
●
When no continuity
exists, replace the
print head unit.
(2) Poor contact of Ca-
ble, head.
A
●
Check continuity be-
tween the Cable,
head terminal and
board ass’y.
●
When no continuity
exists, re-solder.
(3) Bad contact of
Coil, head wire.
A
●
Check the pertinent
Coil, head wire end
and Cable, head sol-
dered section.
●
If poor soldering,
resolder.
(4) Disconnection or
burnt-out of Coil,
head
B
●
Check that resistance
for the pertinent head
coil meets the rating.
(approx. 1.3-ohm at
25°C)
●
When resistance
does not match with
the rating, replace
the print head unit.
(5) Malfunction of
Coil, head
B
●
Check that the clamp
shaft and print lever
for the pertinent head
operte smoothly
●
When they do not op-
erate smoothly, re-
place the print head
unit.
5. Intermittent
dot missing
Intermittent dot
missing for cer-
tain head
(1) Poor contact of Ca-
ble, head
A
●
Refer to Phenome-
non (4) and Cause
(2).
●
When no continuity
exists, re-solder.
(2) Poor contact of
Coil, head wire
A
●
Refer to Phenome-
non (4) and Cause
(3).
●
When no continuity
exists, re-solder.
(3) Malfunction of
Coil, head
B
●
Refer to Phenome-
non (4) and Cause.
●
In case of melfunc-
tion, replace the head
unit.
Intermittent dot
missing occurs
continuously.
Poor contact of Cable,
head
A
●
Check continuity be-
tween the common
line terminal for Ca-
ble, haed and the
board ass’y.
●
When no continuity
exists, re-solder.
6. Fluctuation of
letter width
The letter width
for the certain
columns chang-
es.
(1) Worn out of dam-
age to the gears
B
●
Check that motor
gear, reduction gear,
the Cam trigger unit
gear are not worn out
or dameged.
●
Replace the parts
(motor unit, Cam
trigger unit).
(2) The cam groove on
the Cam trigger
unit is worn out.
B
●
Check that the cam
groove on the Cam
trigger unit is not
worn.
●
Replace the Cam
trigger unit.
Level
Cause
Condition
Phenomenon
Check point and
method
Repair method
Model M190G Technical Manual
Table 2.2 Repairing guide
