Defective Message Displaying (Lcd) - Kyocera FS-1900 Service Manual

(8) Defective message displaying (LCD)

Problem
No message appears
on the message
display (LCD),
though the message
background is
faintly illuminated..
(Power is supplied
to the LCD controller
board [KP-738] .)
No message appears
on the message
display (LCD), even
thought the message
background does not
illuminate faintly.
(The power is not
supplied to the LCD
controller board
[KP-738].)
NOTE: If the corrective action above does not solve the problem, there might be a short circuit in
the respective circuit. Check the conductivity of the each terminals ( ground, 5 V and 24 V power
line) of the circuit board. If a short circuit is detected, replace the circuit board.
FS-1900
Suggested causes
Defective main board (system DIMM board
[KP-893]).
Defective LCD controller board (KP-738).
Defective engine board (KP-864).
Improper connection of harness (S02402)
between LCD controller board (KP-738) and
engine relay board (KP-760).
Improper connection of harness (S02405)
between engine board (KP-864) and engine
relay board (KP-760).
Defective main board (system DIMM [board
KP-893]).
Defective LCD controller board (KP-738).
Defective engine board (KP-864).
Improper connection of harness (S02402)
between LCD controller board (KP-738) and
engine relay board (KP-760).
Improper connection of harness (S02405)
between engine board (KP-864) and engine
relay board (KP-760).
Broken power cord.
The power cord is not plugged in properly.
No electricity at the power outlet.
Defective power supply unit.
6-26
Corrective action
Replace main board
(system DIMM [board]).
Replace LCD controller
board (KP-738).
Replace engine board
(KP-864).
Reinsert the connector.
Reinsert the connector.
Replace main board
(system DIMM [board]).
Replace LCD controller
board (KP-738).
Replace engine board
(KP-864).
Reinsert the connector.
Reinsert the connector.
Replace the power cord.
C h e c k t h e c o n t a c t
between the printer's AC
inlet and the outlet.
Measure the AC power
voltage at the outlet.
Replace the power supply
unit. See page 5-22.