Service manual

EPSON LX-300+ Revision A
Troubleshooting Troubleshooting 59
Table 3-3. Control Panel LED Does Not Light On.
Cause Check Point Y/N Solution
Blowout of a fuse
on the power
board.
Is a fuse on the
power board blew
out?
YES
Check the electric circuit and
printer mechanism. If there is
no short circuit, replace the
fuse.
Connector is not
connected to the
power board.
Are connectors
connected to the
power board
properly?
NO Replace the power board.
Power switch is
defective.
Is conductivity of
the switch is OK?
YES Replace the power board.
Power board is
defective.
Are +5VDC and
+35VDC OK when
the power is on?
NO Replace the power board.
Power board and
the main board
are not connected
properly.
Is CN8 connected
properly?
NO Connect CN8 properly.
Main board is
defective.
- - Replace the main board.
Control panel
harness is not
connected
properly.
Is the harness of
the control panel
connected
properly?
NO
Connect the harness
properly.
Control panel
board or harness
is defective.
- - Replace the control panel.
Table 3-4. Printer Mechanism Does Not Operate.
Cause Check Point Y/N Solution
Any of CN3 to
CN12 is not
connected to the
main board
properly.
Are all connectors
connected
properly?
NO Connect them properly.
Main board is
defective.
- - Replace the main board.
Printer mechanism
is defective.
--
Replace the printer
mechanism.
Table 3-5. When Power is Applied, the Printer Becomes Fatal Error.
Cause Check Point Y/N Solution
CR motor harness
is not connected
properly.
Is CR motor
harness CN10
connected
properly?
NO Connect it properly.
CR motor is
defective.
- - Replace the CR motor.
HP detector
harness is not
connected
properly
Is HP detector
harness CN3
connected
properly?
NO Connect it properly.
HP detector is
defective.
- - Replace the HP detector.
Power board is
defective.
Is power voltage
normal?
NO Replace the power board.
- - -
Replace the main board and
printer mechanism.