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Table of fault symptoms and countermeasures (for repair)
** The following fault symptoms assume that a product which operated perfectly at the time of shipping has become defective.
Symptom
Individual symptom
1
The power cannot be switched on at all. Blown fuse
Related to the
power supply
Each power supply is normal, but there
is no operation.
2 Display-related
Nothing is displayed on the LCD.
Dark LCD
The LCD display shows incorrect
characters.
Some or all LEDs do not light.
Possible causes
None of the power supplies is put out.
+1.8 V is not put out.
The +3.3 V power supply is not put out.
The +5 V power supply is not put out.
The +7 V power supply is not put out.
The +15 V power supply is not put out.
The +20 V power supply is not put out.
The -15 V power supply is not put out.
Microcomputer-related defect
Defective connection between MAIN-JACK
circuit board and POWER-JACK circuit board
Defective oscillation circuit
Defective reset circuit
Memory-related defects
Defective connection between MAIN and LCD
relay circuit board
Defective connection between relay circuit
board and LCD
Defective LCD control circuit
Defective contrast -15 V power supply
Defective LCD unit
Defective microcomputer on the scratch side
Defective backlight power supply
Defective backlight LED in the LCD
Wire break in the FFC cable of the LCD
circuit board
Defective connection between relay circuit
board and LCD
Defective LCD control circuit
Defective LCD unit
Defective LED parts
Defective connection between MAIN and CP
Defective connection between CP1 and CP3
Defective connection between CP1 and CP5
Defective LED decoding circuit on the CP
circuit board
Defective operation of the UI microcomputer
Defect location, countermeasures
Replace the fuse on the POWER circuit board.
IC1150 and D1140 on the POWER circuit board and
their surroundings
IC20 and D2 on the MAIN circuit board and their
surroundings
Check that +1.8 V is applied to C13 on the MAIN circuit
board.
IC1410 and L1271 on the POWER circuit board and
their surroundings
POWER circuit board fuse protector FP1400
IC1302 and D1261 on the POWER circuit board and
their surroundings
Check that +5 V is applied to C15 on the MAIN circuit
board.
POWER circuit board D1261
Check that +7 V is applied to C19 on the MAIN circuit
board.
IC1201 on the POWER circuit board and its
surroundings
Power circuit board resistor R1211
D1271 on the POWER circuit board and its
surroundings
D1403 on the POWER circuit board and its
surroundings
IC2, IC14, and IC34 on the MAIN circuit board and their
surroundings
Confirmation of the connection cable
Pay attention to the orientation.
X1, X3, X5 on the MAIN circuit board and their
surroundings
Confirm that X1 oscillates at 8 MHz and X3 and X5 at
27 MHz.
IC6 and IC11 on the MAIN circuit board and their
surroundings
Output of +5 V for the output of IC6 on the MAIN circuit
board and output of +3.3 V for the output of IC11
IC23, IC24, IC25, IC36, and IC38 on the MAIN circuit
board
Connection confirmation, connecting cable replacement
Connection confirmation, FFC cable replacement
IC1, IC9, and IC13 on the MAIN circuit board and their
surroundings
IC12, Q7, and Q8 on the MAIN circuit board and their
surroundings
Confirm that approximately -10 V to -13 V is put out to
C6 on the MAIN circuit board.
Replacement of the LCD unit
IC14 on the MAIN circuit board and its surroundings
IC8 on the MAIN circuit board and its surroundings
Confirm that +5 V is put out for the output of IC8.
Replacement of the LCD unit
Replacement of the LCD unit or the FFC cable
Connection confirmation, FFC cable replacement
IC1, IC9, and IC13 on the MAIN circuit board and their
surroundings
Replacement of the LCD unit
Replacement of the respective LEDs
Connection confirmation, FFC cable replacement
Connection confirmation, FFC cable replacement
Connection confirmation, cable replacement
IC3101, IC3102, IC3103, IC3104, Q3101, Q3102,
Q3103, and Q3104 on the CP circuit board and their
surroundings
IC2 on the MAIN circuit board and its surroundings
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