Yamaha MSR400, Service Manual

Page: 14 / 30

MSR400
14
■
INSPECTIONS
1. Measuring conditions
1-1. Measuring voltage: AC 120 V, 60 Hz (U)
AC 230 V, 50 Hz (H, B)
AC 240 V, 50 Hz (A)
AC 220 V, 60 Hz (K)
AC 110 V, 60 Hz (T)
AC 220 V, 50 Hz (O)
1-2. Load resistance: LF: 4
Ω
/ Power capacity 500 W
HF: 16
Ω
/ Power capacity 200 W
1-3. LEVEL control setting: Center click position (+4 dB)
1-4. EQ LOW control setting: Center click position (0)
1-5. EQ HIGH control setting: Center click position (0)
1-6. Room temperature: 24±4
℃
2. Inspections
2-1. Power on muting time:
Check that the muting function is cancelled and the relay turns on in 3±1 seconds after the power switch is turned on.
Also, check the POWER indicator lights up.
2-2. Idling current adjustment:
Adjust VR201 and VR202 so that the voltage between pins 1 and 2 of CN206 and CN207 becomes 1±0.2 mV respectively.
2-3. General inspections:
Measure the following items in condition given below, and check the following values are satisfied.
2-4. Protection circuit test:
Apply DC+5 V (power supply output resistance = 10 k Ω ) between pins 1 and 2 of the connector CN209 and check that the relay
turns off within 1 second. Also, check that it returns automatically within 10 seconds when the DC+5 V is shut off.
Items Conditions Values
Input Output Typical Limited
1 Output power LF LEVEL: Max. 1% THD output 230 W 225 W
HF LEVEL: Max. 80 W 75 W
2 Voltage gain LF –42 dB, 500 Hz input, LEVEL: Max. 26 dB 26±1.5 dB
HF –34 dB, 5 kHz input, LEVEL: Max. 29 dB 29±1.5 dB
3 EQ characteristic LF EQ LOW: Min.(Ref.: 55 Hz, EQ LOW: Center) (Ref: The gain
when the EQ LOW
or HIGH is at the
center click position
as 0 dB) –3 dB –3±1 dB
EQ LOW: Max.(Ref.: 55 Hz, EQ LOW: Center) +3 dB +3±1 dB
HF EQ HIGH: Min.(Ref.: 15 kHz, EQ HIGH: Center) –3 dB –3±1 dB
EQ HIGH: Max.(Ref.: 15 kHz, EQ HIGH: Center) +3 dB +3±1 dB
4 Frequency response
characteristic LF 55 Hz input (Ref.: 500 Hz) (Ref.: 1 W output) +8 dB +8±1 dB
1 kHz input (Ref.: 500 Hz) +1 dB +1±1 dB
2 kHz input (Ref.: 500 Hz) –8 dB –8±2 dB
HF 1 kHz input (Ref.:
6.5
kHz) (Ref.: 1 W output) –2
2.
5 dB –2
2.
5±
3
dB
2 kHz input (Ref.:
6.
5 kHz) –4.5 dB –4.5±1 dB
15 kHz input (Ref.:
6.
5 kHz) +7.5 dB +7.5±2 dB
5 DC offset LF without signal input ±8 mV ±8±20 mV
HF without signal input ±10 mV ±10±20 mV
6 S/N ratio
(with A-weight filter) LF 500 Hz input, LEVEL: Max. 225W output 75 dB 70 dB
HF 5 kHz input, LEVEL: Max. 85 W output 70 dB 65 dB
7 Gain/Efficiency
(Primary side power consumption) LF 500 Hz input 30 W output 110 W 110+10/–30 W
HF 5 kHz input 4 W output 25 W 25±10 W
8 Noise level
(with 20 Hz-20kHz filter) LF LEVEL: Min., grounded with two 600
Ω
resistance 1 mV 1.7 mV
HF LEVEL: Min., grounded with two 600
Ω
resistance 1 mV 1.2 mV