Service manual

7-21
CHAPTER 7 TROUBLESHOOTING PROCEDURES
(1-2)The first line is black display in LCD
Connection between low-
voltage power supply unit and
PU PCB (PRX PCB)
Cord ASSY interconnecting
the low-voltage power supply
unit and the PU PCB (PRX
PCB)
Connection between PU PCB
(PRX PCB) and operator
panel PCB (PRP PCB)
FFC interconnecting the PU
PCB (PRX PCB) and the
operator panel PCB (PRP
PCB).
I/F signal from PU PCB (PRX
PCB) to operator panel PCB
(PRP PCB)
I/F signal from operator panel
PCB (PRP PCB) to PU PCB
(PRX PCB)
Confirmation Items
(1-2-1) Check of connections
(1-2-4)Check of LSI operation
Confirmation Tasks
Check to see if the cord from the lower-voltage power supply is
connected properly to the POWER connector of the PU PCB
(PRX PCB).
Check for any incomplete connection or skew insertion.
Check to see if the cord has any wire breakage.
Check to see if the cord has any peel-off of the covering.
Check for any fault in the cord ASSY, such as dislocated wire,
etc.
Check to see if the wires are properly connected on a 1-pin to 1-
pin basis.
Check to see if the 7-pin FFC is properly plugged into the OPE
connector of the PU PCB (PRX PCB).
Check to see if the 7-pin FFC is properly plugged into the CN
connector of the operator panel PCB (PRP PCB).
Check for any incomplete connection or skew insertion.
Check for wire breakage with a circuit-tester. Also, check
visually for peel-off of the covering.
Check to see if there is signal output through the OPE
connector of the PU PCB (PRX PCB)
Pin 1: CLK
Pin 4: Transmitting data (Transmission of PU PCB)
Pin 6: CLR
The signal is permanently output if the PCB is normal.
Check to see if there is signal output through the OPE
connector of the PU PCB (PRX PCB)
Pin 3: Receiving data (Reception of PU PCB)
The signal is permanently output if the PCB is normal.
Action at NG
Redo the insertion of
the cord properly.
Replace the cord with a
normal one.
Redo the insertion of
the cord properly.
Replace the FFC with a
normal one.
Replace the operator
panel PCB (PRP PCB).
Replace the operator
panel PCB (PRP PCB).