Pioneer SC-82 Service Manual page 33

5
DIGITAL AMP BLOCK FLOWCHART
1) No Sound
Power
No
Distribution
Status
Yes
Any Switching
Residual Waveform existed No
in Speaker Output* ?
(Sine wave = Approx.
450 KHz, 0.7V rms) Precautions for checking the speaker output
*
For the channel shown below, positive and negative of
SP terminal are inverted.
Yes
surround ch :
surround back ch :
Audio Signal Input
Check how far the
signal is passing
No
Signal exists just
before Driver IC (IC4101) ?
(Waveform 1 and 2)*
* : Refer to D AMP_SS ASSY (2/6)
Yes
NOTE : Wiring number listed is the example of Front L-ch
2) Diagnosis Flow Chart from Error Symptom
Failure locating method from error symptom is available as diagnosis after product shutdown.
Diagnosis Flow Chart from error symptom due to Amplifier Section is shown here.
Abnormality
Detection on
AMP Power
Voltage (BERR)
Over Current
(IC4101) Output (13pin) seen
Detection (OL)
DC Detection
TEMPERR
BERR Conductivity
Failure Detection
(CERR)
5
6
Approx. DC 2V
Speaker Output ?
The black terminal is HOT
and the red terminal is ground.
MUTE cleared ?
Check MUTE Control
voltage (Q4109 Base)
V = -12V (Normally)
Shorted MOSFET (Q4101, Q4102)
There is a problem
No
in Conduction of Power
Failure BERR Detection Circuit
Supply Connector* ?
(around Q4022, Q4024)
*: (CN4001, CN4002,
Yes CN4003, CN4004)
Check Connector Conductivity
Oscillation
Waveform on Driver IC
Failure around Driver ->
No
Replace Driver IC
just in a moment
at restarting?
Yes
Failure around ZOBEL Detection
Circuit (Q4104, etc)
Perform impedance check on
Audio Output Line vs. Power Supply
Parts Failure after AMPLPF
(L4100, C4101)
Failure in MOSFET (Q4101, Q4102)
Check Power Supply on
Temperature Detection Circuit
(around R4181 and Q4117)
Check XBERR Line Conductivity
D AMP_SS ASSY CN4000-6pin to
DISPLAY ASSY CN6001-31pin.
6
7
Go to 2) Diagnosis Flow Chart
from Error Symptom if immediate
shut down happens by the
Protection Circuit.
Check LPF COIL Conductivity
(L4100)
No
exists in Check each Power Supply of
Driver IC (IC4101)
Check Relay (RY4100) is ON
Yes
Check Voltage of Driver IC
CSD Port (2pin)
No
Check MUTE Control Line
Yes
Check the four block ASSY of
D AMP_SS ASSY
Failure Driver IC (IC4101)
Cause of being BERR
When B-Power Supply Voltage falls below + 20 V
Cause of being OL
At Over Current Detected (Not worked with no-load)
At Driver IC not Oscillated
At ZOBEL Detection Circuit Activated
When B-Power Supply Voltage exceeds + 75 V
Parts Failure after AMPLPF (L4100, Q4101)
Cause of being DC
When DC 7V or above is output in Audio Output Line
Cause of being TEMPERR
When MOSFET Temperature exceeds approx. 120 degrees
When MOSFET temperature is suddenly increased
from
SC-82
7
8
A
B
C
D
E
F
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