Onkyo TX-SR876 - Condition of Protect Mode; Condition of Power Supply Voltage Control; Condition of Cooling Fan Operation

TX-SR876/SA876
OPERATION CHECK-4
Condition of Protect Mode
Condition of Power Supply Voltage Control
Condition of Cooling Fan Operation
The unit will go into Protect mode under the following conditions.
(T: Thermal sensor temperature)
The power supply voltage(VH, VM or VL) for power amplifiers is changed by the relays: RL6601, 6602, 6611, 6612 on NAPS-9040.
VH > VM > VL
T : Thermal sensor temperature
VOLH : Pin #99 input voltage of Main microprocessor: Q7001 (Refer to SD-4:D5 and SD-8:D2 of SCHEMATIC DIAGRAMS)
The sum of dc voltage of 7 channel speaker outputs is more than 7 V.
This condition is equivalent to OPERATION CHECK-2. Refer to the page 2.
Test wave form:
The cooling fan will stop or rotate under the following conditions.
Immediately T <= -30 C
or
Immediately T > 110 C
1. Thermal condition
2. DC voltage condition
Protect will be On if speaker output ac current >= 35 A.
Protect will not be On if speaker output ac current >= 11.7 A and < 35A.
3. Current condition
2 msec
2 msec
20 msec
VH: 0V < VOLH < 0.4V
and
T < 85 C
VM: 0.4V < VOLH < 2.0V
and
T < 85 C
VL: 2.0V < VOLH < 3.3V(Vcc)
and
T < 85 C
VL: T > 85 C
VM: 0V < VOLH < 0.4V
and
T < 85 C
VL: 0.4V < VOLH < 2.0V
and
T < 85 C
VL: 2.0V < VOLH < 3.3V(Vcc)
and
T < 85 C
VL: T > 85 C
Conditions:
Speaker impedance = 6 or 8 ohm Speaker impedance = 4 ohm or BTL
Mid
Speed
Mid
Speed
Mid
Speed
High
Seed
High
Seed
High
Seed
High
Seed
High
Seed
Low
Speed
Thermal Sensor Temperature(T)
Stop
Stop
Stop
0V
60 C
70 C
80 C
0.4V
2.0V
VOLH
“VOLH=0.4V” is equivalent to 0.8W(8 ohm, 7 ch)
“VOLH=2.0V” is equivalent to Max power(8 ohm, 3 ch)
Note:
DSP output max.
DSP output max.