Service manual

REPAIR
SERVICE MANUAL
Troubleshooting
3-7
Troubleshooting Tables
Problem:
Nothing happens when the power is switched on (nothing appears on the LCD).
Points to Check Probable Cause Corrective Action Repair
Is (at least) about +16 V present on
the output plug if the AC adapter?
Defective AC adapter Replace the AC
adapter.
Is fuse F1 on the Switch PCB OK? Blown fuse Replace the Fuse.
Are harnesses CN1 on the Switch
PCB properly connected?
Harnesses improperly
connected.
Replace the Switch
PCB.
Rework the
connectors.
Is about +16V present at CN1 on the
Switch PCB?
Defective Switch PCB Replace the Switch
PCB.
Is +5V present on the Main PCB? Defective ZD7 or Q12
(Main PCB)
Replace the Main
PCB.
Replace ZD7,
Q12.
Problem:
When the power is switched on, the LCD display operates but the carrier does not
return to its home position.
Points to Check Probable Cause Corrective Action Repair
With motor cable disconnected, is
+24 V present at CN3, pin 5 on the
Main PCB?
Defective Q6 (Main
PCB)
Replace the Main
PCB
Replace Q6.
Is resistance value across each of
the phases and COM terminal (pin
5) of the carriage motor correct?
(about 45
Ω
) Phases
→
;(5-1); B(5-
2); ‚b(5-3); D(5-4)
Broken wire in the
carriage motor
assembly (broken wire
in the carriage motor)
(defective connector)
Replace carriage
motor assembly.
Are carriage motor drive pulse
output from pin 150-153 of #8 just
after power is switched on ? (Use
an oscilloscope.)
Defective #8 (Main
PCB)
Replace the Main
PCB.
Replace #8.
Is output at the pin of transistors Q1-
Q4 on and off according the drive
pulses indicated above?
Defective transistor
Q1-Q4 or circuit on the
Main PCB
Replace the Main
PCB.
Replace Q1-
Q4.
Does the carriage motor
occasionally stall?
Incorrect motor phase
at home position (start
up).
Adjust motor phase at
home position (see
Chapter 4 "INK JET
PRINTER
ASSEMBLY").
Problem:
When the power is switched on, the carrier moves to the right but cannot detect its
home position.
Points to Check Probable Cause Corrective Action Repair
Is the carriage index (home position)
switch open?
CA index switch is not
adjusted correctly.
Readjust.
1
2
3