Yamaha EMX 5000-12, Service Manual

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45
EMX5000-12/20
2 GAIN
• Input a -22.0dBs signal to the input terminal and check that +22.2
±
2 dBs output is obtained.
3 FREQUENCY RESPONSE
• Input -22.0dBs signals to the input terminal and check that the output voltage when the signal frequency is 20Hz or 20kHz is
within the range of +1/-3dB with 1kHz used as a reference.
C. OTHER INSPECTION
1
POWER VOLTAGE VARIATION
• Check that no abnormality occurs with operation even when the power voltage is varied by
±
10%.
D. FACTORY SETTINGS
• EQ (GAIN), GEQ, PAN, BAL CENTER
• PROGRAM select 1
• All VR/FADER controls other than above MINIMUM
• All push switches OFF (light off)
• PHANTOM switch OFF
• SIGNAL SELECT switch MAIN (L, R)
• POWER SELECT switch 500W+500W
• YAMAHA SPEAKER PROCESSING switch ON
INSPECTION OF SIGNAL SELECT switch BRIDGE
1 PREPARATIONS
• Input terminal: ST BUS IN 1 L/MONO
• SIGNAL SELECT switch: MONO-RIDGE
• POWER SELECT switch: 500W+500W
• Output terminal: SPEAKER A1 (1+, 2+)
• Load resistance: 8 ohm (1000W or more)
Unless otherwise specified, the load resistance of the speakers should be connected only when performing inspection.
• Set all the INPUT CH1 to 20 (EMX5000-20) / CH1 to 12 (EMX500-12), ST SUB IN 2 and 2TR IN level controls to the MIN position.
• Other than the above, use the same settings as described under “Inspection 1” for inspection.
• Connection of measuring equipment
4
Ω
1+
4
Ω
2+
Input of measuring equipment
GND of measuring equipment
SPEAKON
(Connector NL4FC)
11 PC LIMITER CIRCUIT, LIMITER CIRCUIT
• With 1
Ω
load resistance (
±
5%, 100W) connected to the output terminal, input a 0dBs signal to the input terminal and observe
the output terminal using an oscilloscope. At this time, the protection circuit should function to shut off the output, the LIMITER
indicator should light up and the output should be restored automatically within 5 seconds when the input signal is stopped.
12 EFFICIENCY
• Input a 1kHz, -15dBs signal and check that the primary power is 360
±
50W. If the primary power is not within the specified
range, adjust the input level so that 15.8V (26.2dBs) output is obtained at SPEAKER S and take measurement again.