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Specifications ........................................................................... 1
1. SERVICING NOTE ....................................................... 2
2. GENERAL ....................................................................... 3
3. DISASSEMBLY
3-1. Lid ASSY, Upper ........................................................ 5
3-2. Digital Board .............................................................. 5
3-3. Unit, Switch ................................................................ 6
3-4. Jack Board .................................................................. 6
3-5. Main Board ................................................................. 6
4. DIAGRAMS
4-1. Explanation of IC Terminals ....................................... 7
4-2. Block Diagrams .......................................................... 9
4-3. Printed Wiring Boards (Main Section) ...................... 11
4-4. Schematic Diagram (Main Section) ......................... 13
4-5. Printed Wiring Boards (Digital Section) .................. 17
4-6. Schematic Diagram (Digital Section) ....................... 18
5. EXPLODED VIEWS
5-1. Case Section ............................................................. 23
5-2. Main Board Section .................................................. 24
6. ELECTRICAL PARTS LIST .................................... 25
Flexible Circuit Board Repairing
¥ Keep the temperature of the soldering iron around 270¡C during
repairing.
¥ Do not touch the soldering iron on the same conductor of the
circuit board (within 3 times).
¥ Be careful not to apply force on the conductor when soldering or
unsoldering.
Notes on chip component replacement
¥ Never reuse a disconnected chip component.
¥ Notice that the minus side of a tantalum capacitor may be dam-
aged by heat.
TABLE OF CONTENTS
Jig (J-2503-010-A)
Main boar d
Digital board
SECTION 1
SERVICING NOTE
Using the special connector jig (J-2503-101-A) to connect the main
board and digital board will prove convenient when servicing the
unit with power applied.
Note : Do not apply excessive amounts of flux during replace-
ment of electronic components since this may cause elec-
trical shorts due to moisture.
Wipe off flux after electronic components exchange.
CAUTION ON REPLACING FLASH MEMORY
The BAD-BLOCK check* must be executed, when the flash
memory (IC701) in this set was replaced.
The set will not operation normally, unless this check is finished.
* The BAD-BLOCK check detects an area (bad-block) in the flash
memory where data validity cannot be guaranteed, and saves
this information in the TOC-AREA so that a bad-block is not
used.
BAD-BLOCK check procedure :
1. Apply 3V from regulated power supply to the battery
terminals.
2. Once the power is supplied, the check starts and then
proceeds for approx. 3 minutes. (Be sure to keep applying
the power during the check)
3. When the check completes, the result is shown as bellows.
OK : Only the LCD back light LED (D503, 504) turns on.
NG : Red LED blinks or turns on or green LED turns on in
the OPR LED (D502),
4. In case of OK, press the STOP button.
Note :
¥ In case of NG, check system control IC (IC704), flash memory
IC (IC701) and the peripheral circuit. (Particularly, check care-
fully the soldering of the flash memory)
¥ After finishing the BAD-BLOCK check, assemble the set, load
the dry battery, and confirm if the set operates normally.
