Circuit Description - Pioneer SC-82 Service Manual

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5.2 CIRCUIT DESCRIPTION

[1] Protection Circuit Process List
A
Amplifier Circuit
Item Purpose
Detects MOS FET
Overheat
temperature of amplifier output
detection
stage
B
Detects DC of amplifier output
DC
detection (After LPF)
C
Protects overcurrent by Zobel
Zobel Resistance when high power
detection output of higher frequency
continued
Protects overcurrent of MOS
Overcurrent FET in output stage when
detection
overcurrent flows at the output
stage
D
Amplifier
Power
Detects abnormal in the
Supply
Amplifier Power Supply
failure
detection
BERR
conductivity
Detects XBERR line
failure
conductivity failure
detection
Fan Detects a Fan not rotating by
E
loose connector or Fan lock
abnormality
detection when controling the Fan rotation
[How to Enter Release Mode]
During Standby mode, simultaneously press and hold the "TUNE [] " and "ZONE2 ON/OFF" keys for 5 seconds.
F
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2
Detection Method
Detects when TEMPERR5 port
becomes "L" in case of the Flashes "OVERHEAT"
Shuts down when
detecting temperature exceeds
120°C or rapid change by short abnormality continues for
more than 3 seconds.
cuicuit of speaker terminals.
(IC6001 24pin)
Detects when AMPTEMP port
becomes below 1.6V at NTC
Fan rotates by power-on.
Thermistor detect circuit.
(IC6001 64pin)
MUTE on and Speaker
Relay off.
Flashes "AMP ERR".
Shuts down when
abnormality continues for
more than 3 seconds.
Detects when SP output exceeds
DC ± 7V and XDCERR port
becomes "L". (IC6001 21pin)
MUTE on and Speaker
Relay off.
Flashes "AMP ERR".
Shuts down when
abnormality continues for
more than 3 seconds.
Detects XOLERR port becomes
Shuts down
"L". (IC6001 13pin)
Detects XOLERR port becomes
Shuts down
"L". (IC6001 13pin)
Detects B-Power Supply Voltage
exceeds ± 75V and XOLERR port
becomes "L". (IC6001 13pin)
Shuts down
Detects B-Power Supply Voltage
falls below ± 20V and XBERR port
becomes "L". (IC6001 75pin)
Detects when XBERR port
becomes "M". (approx. 2.5V)
Shuts down
(IC6001 75pin)
Flashes "FAN STOP"
Shuts down when
Detects when XFANERR port
abnormality continues for
becomes "L". (IC6001 28pin)
more than 3 seconds.
SC-82
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3
Status of Equipment Warning Indication
Blinks FL OFF LED
indicator.
Blinks ADVANCED
MCACC LED
Blinks FL OFF LED
indicator.
Blinks iPod iPhone LED
Blinks iPod iPhone LED
Blinks iPod iPhone LED Recoverable by power-on.
Blinks ADVANCED
MCACC LED
Blinks iPod iPhone LED Recoverable by power-on.
Blinks iPod iPhone LED
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4
Remarks
Recoverable by power-on
after shutdown in 1 minute.
AMPTEMP voltage
[US Model Only]
5V-2.9V : FANLOW
2.9V or less : FANHIGH
[Except US Model]
5V-3.8V : FANSTOP
3.8V-2.9V : FANLOW
2.9V or less : FANHIGH
In case of detecting DC
abnormality during
power-on sequence after
the DC was once detected.
Recoverable by only DC
DETECT cancel.
Refer to "How to Enter
Release Mode" .
In case of detecting DC
abnormality during normal
operation. Recoverable by
power-on after 1 minute.
Recoverable by power-on
Recoverable by power-on
Recoverable by only DC
DETECT cancel.
Refer to "How to Enter
Release Mode" .
Recoverable by power-on
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