Yamaha EMX312SC, Service Manual, Page: 55 / 140

EMX512SC/EMX312SC
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Note:
• Noise should be measured with a DIN AUDIO filter.
3-4 Protection Circuit for DC Fault
Disconnect load resistance from the output terminal and set the LOW equalizer gain control of channel 5/6 to maximum and the
POWER AMP switch to MAIN L/R. Then check the POWER indicator does not turn off when inputting the 1 Hz, –5 dBu signal from
LINE L terminal of channel 5/6.
3-5 Frequency Response
<YS Processing switch: OFF>
Input the 20 Hz, 1 kHz and 20 kHz, –27 dBu signal and check the output terminal level is +1±3 dB compared with the 1 kHz.
<YS Processing switch: ON>
Input the 70 Hz, –27 dBu signal and check the output terminal level is +6.5±2 dB compared with the 1 kHz when the YS Processing
switch is set to OFF. Also check the YS Processing indicator lights up.
3-6 VI Limiter and Compressor
Connect 1
Ω
(±5 %) load resistance to the output terminal and input the 1 kHz, –19 dBu signal. Then check the output terminal
voltage is within the range specified in the table 3-6-1 and the distortion is less than 8 %. Also check the LIMITER indicator lights up.
Notes:
• Each channel should be inspected separately.
• Finish this inspection within 30 seconds.
3-7 Power Consumption
<EMX512SC/EMX312SC>
Input no signal and set the MONITOR MASTER control and MAIN MASTER control to minimum. Then check the primary electrical
power is within the range specified in the table 3-7-1.
3-7-1 Preparation
<EMX512SC only>
• Input the 1 kHz, –10 dBu signal.
• Adjust the MONITOR MASTER control so that the output terminal voltage of the SPEAKERS B2 terminal is +22±0.1 dBu.
• Adjust the MAIN MASTER control so that the output terminal voltage of the SPEAKERS A2 terminal is +22±0.1 dBu.
• Do not touch the MONITOR MASTER control and MAIN MASTER control until this inspection is finished.
3-7-2 Inspection
Input the 1 kHz, –5.7 dBu sine wave and check the primary electrical power is within the range specified in the table 3-7-2.
Table 3-6-1
SPEAKERS (A2, B2)
EMX512SC 24.5±2 dBu
EMX312SC 22.5±2 dBu
Table 3-7-1
Power Consumption
EMX512SC 40±10 W
EMX312SC 40±10 W
Table 3-7-2
LINE R Power Consumption
EMX512SC –5.7 dBu 330±80 W