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SC-57
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5.2 CIRCUIT DESCRIPTION
[1] Protection Circuit Process List
Amplifier Circuit
Item
Purpose
Detection Method
Status of Equipment
Warning Indication
Remarks
Overheat
detection
Detects MOS FET
temperature of amplifier output
stage
Detects when TEMPERR PORT
becomes "L" in case of the
detecting temperature exceeds
95°C or rapid change by short
cuicuit of speaker terminals.
(IC3001 72pin)
Blinks FL OFF LED
indicator.
Recoverable by power-on
after shutdown in one
minute.
MAXTEMP voltage
5V-1.8V :
FANLOW
1.8V or less : FANHIGH
Detects when MAXTEMP port
becomes below 1.9V at NTC
Thermistor detect circuit.
(IC3001 2pin)
Fan rotates by power-on.
DC
detection
Detects DC of amplifier output
(After LPF)
Detects when SP output exceeds
DC ± 7V and DCERR port
becomes "L". (IC3001 80pin)
MUTE on and Speaker
Relay off.
Flashes “AMP ERR”.
Shuts down when
abnormality continues for
more than 3 seconds.
MUTE on and Speaker
Relay off.
Flashes “AMP ERR”.
Shuts down when
abnormality continues for
more than 3 seconds.
Blinks ADVANCED
MCACC LED
Blinks FL OFF LED
indicator.
In case of detecting DC
abnormality during normal
operation. Recoverable by
power-on after 1 minute.
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” .
Fan
abnormality
detection
Detects a Fan not rotating by
loose connector or Fan lock
when controling the Fan rotation
Detects when FANDET port
becomes "L". (IC3001 87pin)
Flashes "FAN STOP"
Shuts down when
abnormality continues for
more than 3 seconds.
Blinks iPod iPhone iPad
LED
Blinks iPod iPhone iPad
LED
Blinks iPod iPhone iPad
LED
Recoverable by power-on
Recoverable by power-on
Recoverable by power-on
Zobel
detection
Protects overcurrent by Zobel
Resistance when high power
output of higher frequency
continued
Detects OLERR port becomes "L".
(IC3001 71pin)
Shuts down
Shuts down
Shuts down
Overcurrent
detection
Protects overcurrent of MOS
FET in output stage when
overcurrent flows at the output
stage
Detects OLERR port becomes "L".
(IC3001 71pin)
During Standby mode, simultaneously press and hold the "TUNE [
] " and "MULTI-ZONE ON/OFF" keys
for 5 seconds.
[How to Enter Release Mode]
Flashes "OVERHEAT"
Shuts down when
abnormality continues for
more than 3 seconds.
Detects abnormal in the
Amplifier Power Supply
Blinks ADVANCED
MCACC LED
Recoverable by only DC
DETECT cancel.
Refer to “How to Enter
Release Mode” .
Amplifier
Power
Supply
failure
detection
Detects B-Power Supply Voltage
exceeds
± 75V or
falls below
± 20V
and BERR port becomes "L".
(IC3001 84pin)
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