(No.WA122<Rev.002>)4/7
SECTION 2
SPECIFIC SERVICE INSTRUCTIONS
2.1
How to repair a fuse pattern
2.1.1 Purpose of fuse pattern
In order to prevent serious damage on the circuit, fuse pattern is prepared on the GND line of RCA Terminal. This damage may
take due to improper part replacement with a external equipment via RCA line.
2.1.2 Repair Procedure
(1) Check the shorted circuit at the meltdown point.
Need to clean up if the shorted circuit or carbonization happen at the fuse pattern.
(2) Add following part on the fuse pattern.
(3) Check output level.
2.1.3 After finished repair
Due to improper part replacement, this meltdown occurs.
Thus please notice following information when the unit is returned to your customer.
Things to be checked before installing the unit.
(1) Check the GND line of external amplifier or other equipment which must connect properly.
(2) Check whether the GND line is not short-circuited with the battery terminal. (do not short-circuit these lines)
2.2
Components description
2.2.1 AUDIO UNIT (X09-9220-10)
Part Number
Part Name
SPEC
F53-0513-08
PATTERN FUSE
4A
Meltdown point
Ref. No.
Application / Function
Operation / Condition / Compatibility
D1, D2, D3, D4, D101,
D102, D103, D104
Electrostatic protection diode
Protects the circuit against static electricity that enters through
the RCA or SP-IN connection.
IC10, IC11
Input buffer OP-AMP
Reduces the noise of electrical components during RCA input
IC1
Input OP-AMP
Isolation AMP for RCA IN or SP IN
D5 - D8, D105 - D108,
D203
TMS control diode
Clips the audio signal and lowers the AMP output level when
the temperature of the set is high.
IC6
TMS control OP-AMP
IC12
AMP gain adjustment OP-AMP
+10dB AMP
IC2, IC3
OP-AMP for LPF
fc: 45 kHz
Q3, Q103
Transistor for output ON/OFF control of D-
AMP IC
AMP IC output: OFF (when transistor is ON)
IC4, IC5
D-AMP IC
2ch AMP IC for analog input and digital output
D9, D10, D109, D110
Diode for D-AMP IC's overcurrent detec-
tion circuit
D11, D12, D111, D112
Diode for D-AMP IC's charge pump
Q232, Q233
Transistor for -26dB ATT circuit control
Q233: ON
→
Q232: ON
→
ATT ON
