Yamaha-EMX-660-Service-Manual电路原理图.pdf
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1、1 EMX660 SERVICE MANUAL PA 011519 20000608-74800 1.45K-479 Printed in Japan 2000.06 HAMAMATSU, JAPAN CONTENTS SPECIFICATIONS. 3/5 DIMENSIONS. 6 PANEL LAYOUT. 7 BLOCK for example, there should be no oscillation. Especially, check that no oscillation occurs even if the EQ HIGH is at maximum. -73-71 -8
2、8 Table 6Unit: dBs Operation Press ON SW. Set LEVEL control to min. position. - - Depress FOOT SW. - - - Check for: (at MONITOR OUT) No output (-53dBs or less) DIN AUDIO -53dBs or less DINdBsDIO Output obtained Output not obtained (-53dBs or less) DIN AUDIO -30dBs or less DIN AUDIO and full output a
3、re repeated every time FOOT SW is depressed. Output not obtained (-53dBs or less) DIN AUDIO 4.2 1dB attenuated from full output +10 3dBs of full output PGM Switch VO. ECHO1 VO. ECHO2 VO.REV.1 VO.REV.2 HALL1 HALL2 ROOM PLATE 21 EMX660 3.Power Amplifier Part 3-1Setting Conditions Setting conditions ar
4、e as follows unless otherwise specified. 3-2Power ON Muting The muting relay should be released 2.5 +/- 1 seconds after the power switch is turned on. 3-3Speaker Terminal DC Voltage When input terminals are grounded, confirm that each output terminal voltage is 0 +/- 100 mV. 3-4Gain Check that +22 2
5、.0dBs output voltage is obtained when a -26dBs signal is input to the input terminal. Perform the same check under the setting conditions of POWER AMP switch at MAIN-MAIN and the output terminals at POWER AMP 1G and POWER AMP 2B. 3-5Frequency Response Apply a -26dBs signal to the input terminal and
6、check that the output voltage when the signal frequency is 20Hz and 20kHz is within +1 and -3dB ranges respectively, using the output voltage at 1kHz as reference. 3-6Harmonic Distortion Apply a 1 kHz sine wave signal to the input; the output level should be 300 W/4 ohms (33.0 dBs/ch); the distortio
7、n ratio should be less than 0.5 %. Apply a sine wave signal of 20 Hz, 1 kHz and 20 kHz separately to the input; the output level should be 150 W/4 ohms (30.0 dBs); the distortion ratio should be less than 0.5 %. Do this inspection within 30 seconds. 3-7Residual Noise Set the MASTER level controls (M
8、ONITOR and MAIN) at minimum; the residual noise at the output terminal should be less than -65 dBs. Note: Use DIN-AUDIO filter. 3-8Stability Apply a 10 kHz -26 dBs rectangular signal to the input and connect a capacitor (10 pF to 0.47 F) parallel to the 4 ohm load resistor, or connect an inductor (1
9、0H to 0.47 H) serial to the 4 ohms load resistor. Confirm that the output signal is as illustrated below. Overshoot:Vp/Vo 1.8 Ringing:5 waves and less than 5 waves Vp Vo Next, only connect a capacitor (10 pF to 0.47F) to the SPEAKERS terminal as a load, and confirm that the output is as follows: Ove
10、rshoot:Vp/Vo 2.5 Ringing:It should end within 7 waves; there is no oscillation. INPUT CH5 LINE1 MAIN-MONITOR POWER AMP 1A, POWER AMP 2A 4 ohm (more than 300W) Connect the load resistor of SPEAKER OUT only when inspecting the power amplifier section unless otherwise specified. Minimum Input terminal:
11、 POWER AMP switch: Output terminal: Output Load: INPUT CH1 - 4, CH6 LEVEL control: = = EMX660 22 3-9Protection Apply a 10 Hz sine wave signal to the input; increase the input signal so that the output signal is clipped. Confirm that the protection function operates and that the speaker relay does no
12、t open. When a 1 Hz, 6 Vp-p (8.7 dBs) sine wave signal is applied to the input, confirm that the protection function operates within 2 seconds and the speaker relay is turned off. When the input signal is turned off, confirm that the protection function stops and the speaker relay automatically turn
13、s on within 5 seconds. 3-10 PC Limiter and Limiter Apply a 1 kHz -20 dBs sine wave signal to the input and then connect a 1 ohm ( +/- 5% 100 W) resistor; confirm that the output signal is Vp-p 25V and that the signal is not rectangular. 3-11 LIMITER Indicator When a 1 kHz -10.8 dBs sine wave signal
14、is applied to the input, the LIMITER indicator should light up. 3-12 Efficiency When the output of POEWR AMP1 and 2 is adjuster to 12.2V (24.0 dBs), confirm that the primary power is 180 +/- 50W. 4.Main Bridge 4-1Setting Conditions Input Terminal:INPUT CH 5 LINE 1 POWER AMP switch:MAIN BRIDGE Measur
15、ing Output Terminal:BRIDGE Output Load:8 ohm (more than 600 W) INPUT CH 1- 4, CH 6 LEVEL level control:Minimum Note: Other control settings are the same as those for the mixer in section 2-3. 4-2Connection TipMeasuring instruments input 4 ohms Phone PlugMeasuring instruments ground 4 ohms Sleeve 4-3
16、Gain Apply a 1 kHz -26.0 dBs sine wave signal to the input; confirm that the output levels is are +22.0 2 dBs. 4-4Frequency Response Apply a -26dBs signal to the input terminal and check that the output voltage when the signal frequency is 20Hz and 20kHz is within +1 and -6dB ranges respectively, us
17、ing the output voltage at 1kHz as reference. 5.Power Supply Fluctuation There should be no operational problems when the power voltage is varied within +/- 10% of the nominal voltage. = 23 EMX660 EMX660 24 25 EMX660 EMX660 26 27 EMX660 EMX660 28 TROUBLE SHOOTING ProblemCauseAction Sound is no longer
18、 out- put from the speakers. The POWER indicator is dark. The load on this device was too great, and the protection circuit for the inter- nal transformer has operated. Possi- ble reasons for the excessive load are an excessive input to the device, or inap- propriate ventilation. Please wait. When t
19、he device cools off, normal operation will resume automatically. However, please check the following two points to prevent the problem from recurring. If the input to this device is greater than the nominal level, lower the input to the nominal level. If the device is not ventilated suffi ciently, r
20、efer to the cau- tions given at the beginning of this manual and take appropriate measures to insure adequate ventila- tion. The POWER indicator is lit. The load on the amplifi er of this device was too great, and the protection cir- cuit for the amplifier has operated. Possible reasons for the exce
21、ssive load are an excessive level setting in the channel control section or main section, insuffi cient ventilation, or insuffi cient load impedance of the connected speak- ers. Please wait. When the device cools off, normal operation will resume automatically. However, please check the following th
22、ree points to prevent the problem from recurring. If the level setting is excessive, lower it to the nomi- nal level. You can refer to the peak level indicators of the main section when doing so. If the device is not ventilated suffi ciently, refer to the cautions given at the beginning of this manu
23、al and take appropriate measures to insure adequate ven- tilation. If the load impedance (including a short) is too low, and change the connections so that the impedance is correct. Other Connections between devices have come loose. Inspect the connections, and correct any faulty con- nections. Othe
24、r The device may have malfunctioned. WARNING Components having special characteristics are marked and must be replaced with parts having specification equal to those originally installed. Notes : DESTINATION ABBREVIATIONS The numbers “QTY” show quantities for each unit. The parts with “-” in “PART N
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