Yamaha EMX 5000-12, Руководство по обслуживанию

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EMX5000-12/20
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6 FREQUENCY RESPONSE
• YAMAHA SPEAKERS PROCESSING switch OFF
Input -19 dBs signal to the input terminal and check that the output voltage at 20Hz and 20kHz signal frequency is within the
range of +1/-3dB with 1kHz used as a reference.
• YAMAHA SPEAKERS PROCESSING switch ON
Input 70Hz/-19dBs signal to the input terminal and check that the output voltage when YAMAHA SPEAKERS PROCESSING
switch is turned off is within the range of +6.2
±
2dB with 1kHz output voltage used as a reference.
7 TOTAL HARMONIC DISTORTION
• Input a 1kHz signal to the input terminal and check that the total harmonic distortion is 0.5% or less when 500W + 500W/4
Ω
(35.2 dBs) output is obtained.
• Also, input 20Hz, 1kHz and 20kHz signals to the input terminal and check that the total harmonic distortion is 0.5% or less
when 250W + 250W/4
Ω
(32.2 dBs) signal is obtained at the output terminal.
* Be sure to finish this inspection within 30 seconds.
8 RESIDUAL NOISE
• Set the ST MASTER level control to the MIN position and check that the noise level at the output terminal is -65dBs. Use care
so that the measurement is not affected by the induction noise. (Use the DIN audio filter.)
9 STABILITY
• With 10kHz, -3.2dBs rectangular wave inputted, connect 10pF to 0.47
µ
F static capacitance in parallel with 4
Ω
load resistance
or 10
µ
H to 0.47H inductance in series and check that the following requirements are satisfied.
• Disconnect 4
Ω
load resistance to make the load consisting of 10pF to 0.47
µ
F static capacitance only and check that ringing
is within 7 waves at Vp/Vo</=2.5 and no oscillation or the like occurs.
10 PROTECTION CIRCUIT
• With a signal input to POWER AMP IN (L), clip the output waveform of the 10Hz signal and check that the protection circuit
functions to prevent the relay from opening.
• Check that the protection circuit functions within 2 seconds to shut off the output when a 1Hz, Vp-p=10V(13.2dBs) signal is
input and the output is restored automatically within 5 seconds when the input signal is stopped.
Vo
Vp
Overshoot: Vp/Vo 1.8
Ringing: Within 5 waves
[Table 5-1] Gain [Unit: dBs]
POWER AMP switch
MAIN L-MAIN R
AUX1-MONO AUX1-AUX2
500W+500W 300W+300W 100W+100W
SPEAKERS A1 (1+, 1-), A2 22.2
±
2.0 20.0
±
2.0 15.2
±
2.0 25.2
±
2.0 25.2
±
2.0
SPEAKERS B1 (1+, 1-), B2
22.2
±
2.0 20.0
±
2.0 15.2
±
2.0 25.2
±
2.0 25.2
±
2.0
SPEAKERS A1 (2+, 2-)
3 Fan
• Short-circuit the 2 J wires within the frame marked FAN-C in the center of the PWR circuit board and check that the fan runs
at a low speed.
4 DC voltage at output terminal
• Check that the DC voltage at the output terminal is 0
±
100mV when the input terminal is grounded.
5 GAIN
• Input a -19 dBs signal to the input terminal and check that the output level of the measured gain is as specified in Table 5-1
when the SIGNAL SELECT switch setting is changed.
Check all the output terminals other than BRIDGE (1+, 2+). For SIGNAL SELECT switch MAIN L – MAIN R, also check with
the select position of the POWER SELECT switch changed.