Sony WRR-855B, Service Manual, Page: 15 / 84

2-5
WRR-855B
2-2-2. CPU-342 Mounted Circuit Board
When attaching the CPU-342 mounted circuit board into
the unit, press the A portion as shown below and insert the
CPU-342 mounted circuit board into the connector ( CN-
601 ) of the TUN-8 mounted circuit board firmly so that
the CPU-342 mounted circuit board is securely attached.
2-3. Precautions When Replacing
EEPROM
On the EEPROM (IC702) mounted on the CPU-342 board,
frequency data corresponding to each WRR-855B have
been written. After replacing an EEPROM, it is necessary
to write the corresponding frequency data to the new
EEPROM.
A
CN701
CN601
TUN-8 board
CPU-342 board
2-4. Error Messages
The following error messages will appear if an error is
detected by the built-in self diagnostics function of the
WRR-855B.
Error Contents Countermeasure
Message
Error01 Error in the backup Write the frequency data.
memory.
Error02 PLL synthesizer circuit Check the PLL synthesizer
failed. circuit (IC301, CP301 and
its peripheral circuit) on
the TUN-8 board.
Error03 The circuit voltage in the Check the Q653, IC651/
tuner unit assembly is
TUN-8 board and its
abnormal. peripheral circuit.
TONE The tone signalis not Refer to the section “Muting
present, or the audio OFF Mode” in the Operation
signal output is muted Manual.
because the receiver
received a tonesignal
other than 32.768 MHz
signal.