Epson LQ-670 Service Manual page 111

LQ-670 Service Manual
Symptom
Paper feed PF motor control
operation is is abnormal.
abnormal.
Control panel is Switch, LED or
abnormal. LCD is
abnormal.
Data from the Indication of
host computer is Data
not received communication
correctly. error or data
turns out be
unidentified.
Power can not be turned off.
Default setting values can not be
stored.
5-16
Table 5-13. Repairing the C214 Main Board (Con.)
Condition Cause
PF motor control
circuit is defective.
Control panel
circuit is defective.
Interface
elements are
defective.
CPU is defective.
Signal line(PSC)
of the power
supply board
shorts.
EEPROM is
defective or
defective writing
Checkpoint
Check the phase signal of
pin 8 and output signal of
pin 1 and pin 15 of IC1 or
IC2.
If phase signal of the
motor is not input, gate
array IC10 is defective.
If the drive wave form is
not output, IC1 or IC2 is
defective.
Figure 5-15. Waveform of
the PF Motor Drive
Check the connection
between the harness of the
control panel and main
board.
Check if the harness is
broken or not. If harness is
broken, CPU(IC10) or gate
array IC25 is defective.
Replace the interface cable.
If self-test is performed
normally, interface elements
are defective.
---
Check if pin 20 of the
operation panel becomes
GND level when the power
is turned off.
---
Solution
Replace the main
board, IC1 or IC2.
Replace the main
board or control
panel.
Replace the main
board.
Replace the main
board.
Replace the main
board, power
supply board or
control panel.
Replace the main
board.
Rev. A