Printing Quality Problems - Samsung SRP-275 Service Manual

7-2-2 Printing quality problems

Problem
FPC-head connector is disconnected
with PCB-head ass'y and Printer-
head
Broken common lead of FPC-head
HF motor
rotates
FPC(30pin) between the PCB-head
normally but
ass'y and PCB-main ass'y is broken
no dot printing
is performed
Positional
Printer-head and Platen
Ribbon cassette is absent
Input pulse irregularity
Damaged lead in FPC-head
Positional relationship between the
head and the platen
A certain dot
does not print
FPC(30pin) is failure or disconnected
between PCB-head ass'y and PCB-
main ass'y
Defective Printer-head
Belt tension is loose
Character
width changes
Carriage drive area contamination
irregularly
Carriage drive parts wear or damage
Ribbon cassette is exhausted
Print is very
Head gap is not correct between
faint
head and platen
Defective Printer-head
Rev. 2.00
Probable Cause
relationship between
Level Checkpoint
Check if the FPC-head is
properly inserted
B
connector of head and its
board
Check the
between the common lead of
B
FPC-head
terminals
Check the conductivity of the
B
FPC(30pin)
Check if the gap between the
platen and the pin of head is
B
correct value : 0.40±0.05mm
Check Ribbon cassette's
A
existence
Check firing input pulse with
B
an oscilloscope
Check the conductivity of
B
lead of FPC-head
Check if the gap between the
platen and the pin of head is
B
correct value : 0.40±0.05mm
Check the
B condition of FPC and FPC
failure
Check head response to
B
command with oscilloscope
Check Spring-lever-tension
B
for deformation
Check gears and pulleys for
B dirt deposits or other foreign
matter
Check if there are defective
B
parts among gears
Check for ink of ribbon
A
cassette
B Check the gap
Check head response to
B
command with oscilloscope
- 125 -
SRP-275
Action
If is not, securely
into its
reinsert the FPC-
head
conductivity
Replace the HEAD
unit, if there is no
and other
conductivity
Replace the FPC
(30pin) if there is no
conductivity
Correct the gap
Insert
Ribbon cassette
Replace
PCB-main ass'y
Replace FPC-head
If incorrect,
performed repair with
reference
connected Make sure the
connection and
replace the FPC
Replace
Printer-head
Replace or
reassemble Spring-
lever-tension
Remove any dirt
deposits or foreign
matter
Replace defective
gear
Replace
Ribbon cassette
If incorrect, performed
repair with reference
Replace
Printer-head