Inspection（検査 - Yamaha p5000s Service Manual

I INSPECTION
1. Scope
• This inspection specifications is applied to the power amplifier P5000S/P7000S.
2. Preparation for STEREO/PARALLEL mode
Attenuator
Input terminal
MODE switch
SUBWOOFER/LOW CUT switch : OFF
YS Processing switch
Load resistor
Unless otherwise specified, the operation shall be both channels drive.
DIN AUDIO filter shall be used for the noise level measurements.
Unless otherwise specified, the input signal shall be high quality sine wave.
3. Inspection and Adjustment
3.1 POWER LED, PROTECTION LED and Power on muting time
POWER LED and PROTECTION LED shall light when the POWER switch is turned on.
2.5 +/- 1 seconds after the power switch is turned on, PROTECTION LED shall lights off.
3.2 Fan and TEMP LED
The fan shall operate when short circuit on the two jumper wires that mounted of PS
circuit board marked "FAN-C". The TEMP LED shall lights up when short circuit on the
two jumper wires that marked "TM-C".
3.3 Idle current
Connect the input terminal to the GROUND and adjust VR201 on the PAH circuit board that the DC voltage of
Vb between the pin1 and pin2 of CN101 shall be 0.275 +/- 0.025mV.
After finishing all inspections, adjust the Vb again to 0.5 +/- 0.1mV.
This adjustment should be performed in both channels.
3.4 DC Voltage of output terminal
Connect the input terminal to the GROUND and measure the DC voltage Vdc of the output
terminal shall be 0 +/- 75mV.
3.5 Gain
The output voltage should be +22.1 +/- 0.5dBu when input signal is 1kHz, -10.0dBu.
This inspection shall be performed on PARALLEL mode.
Don't feed input signal to channel B on PARALLEL mode.
Set the input attenuator to -10dB.Input signal is 1kHz, -10dBu.
The output voltage shall be 12.0 +/- 3.0dB.
3.6 Frequency response
Input signals are each 20Hz, 1kHz and 20kHz, -10dBu.
The output voltage shall be 0.0 +/- 0.5dB at 20Hz, -0.5 +/- 0.5dB at 20kHz compared to the 1kHz.
Set MODE switch to PARALLEL.
The inspection process of SUB WOOFER and LOW CUT position as follows.
1) channel A 25Hz
2) channel A 150Hz
3) channel B 25Hz
4) channel B 150Hz
: "0"(MAX)
: cannon connector 2PIN-HOT/3PIN-COLD/1PIN-GND
: STEREO
: OFF
: 8ohms +/- 1%
P5000S /P7000S
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