Japan Cach Machine G356E Service Manual - page 18
16
PHENOMEN
ON
CONDITION CONSIDERABLE
CAUSE
CHECK POINT/
METHOD
REMEDY
Is the head unit over heat?
When the head is over heated, printing is
stop.
Wait for head becomes cool.
Printer
doesn’t work
at all
Printer motor doesn’t
rotate
Stepping signal does not
generated.
Is the stepping signal output from
P13X(U17)?
Is the stepping signal output from U9 or
U10?
Replace U17
Replace U9 or U10
Printer feed
the paper
without
printing
Printer motor does
work correctly
DC power for print head
unit is not output
When pin12(P142) of U17 outputs “H” ,
the head become active.
Replace Q3,Q4.
The FPC for CPU and FD
units connection is broken
Check conduction of FPC.
Replace FPC
Display voltage(-30v) is not
generated
Is PD13 defect?
Replace PD13
Replace converter transformer
Filament voltage (VF1,VF2)
is not generated.
Check the voltage between VF1 and
VF2(tolerance3.46Vrms)
Replace converter transformer
Center tap voltage of
filament is not correct.
Is the cathode voltage of PD14-23.5V?
Replace PD14.
Display doesn’t light
Display tube is broken.
Is the display tube cracked?
Replace the display tube
Abnormal
display
Some ghost are
displayed.
Cut off voltage is generate
from PD21
Is cathode voltage of PD14 –23.5V?
Replace PD14
Specific digit
is not lit
correctly
Key input correct
Trouble in FD driver.
Check the condition of the FPC
Replace FPC
Replace U23,U24
Specific
segment is
not lit
correctly
Display data and time
data are correct.
Trouble in segment drive.
Check the condition of the FPC.
Replace FPC
Replace U22
2 key are depressed
together
Check whethe r any key keeps depressing. Replace key board unit.
Control mode is lock
position
When control lock is released, lock signal
is applied to KR lines(KR0-KR4)
Replace D10
Check conduction of the control key.
Key input
cannot be
accepted
Specific key input
cannot be accepted.
Diodes (D1-D9) are defect.
Check the diode on the output line of
specific key’s key matrix.
Check diode on key
Matrix output.