SERVICE MANUAL - Nexo

NXAMP4x41-5. Other0 dBu is defined as 0.775 Vrms in these inspections.2. Inspection with ordinary modeCondition:• Ground each input terminal via a 600 Ω resistance.• Do not connect the load resistance to the output terminal.2-1. Power ON sequence1) Turn the power switch on. Confirm that the latest firmware version appears on the LCD display.Example of firmware version 1.002) Confirm that all the fans start rotation at low speed within 4 seconds after turning the power switch on.3) Confirm that the following display appears on the LCD within 18 ±3 seconds after turning the power switch on. Alsoconfirm that the POWER LED and only one of the VOLUME LEDs for each channel light up.2-2. Power consumption when idlingMeasure the primary power consumption and confirm that the measured value is 120 ±30 W.2-3. Output terminal DC voltageMeasure the DC voltage (Vdc) of each output terminal and confirm that the measured value is Vdc = 0 ±50 mV.2-4. PEAK indicatorSet this unit to GAIN: 0 dB, VOL: 0 dB.Input the 20 kHz, 15.7 dBu, sine wave to channel 1 input terminal, and confirm that the PEAK indicator of channel 1 flashesor lights. Input the 20 kHz, 13.2 dBu, sine wave, and confirm that the PEAK indicator of channel 1goes off.Perform the same test for channel 2-4 in the same manner.After test, set this unit to GAIN: 0dB, VOL: -90 dB.3. Inspection with attenuation test modeCondition:• Perform each test in this section in the attenuation test mode. (See “TEST PROGRAM 4-14. ATTENUATION test”)• Connect an 8 Ω load resistor to each output terminal.• Ground each input terminal via a 600 Ω resistor.3-1. Residual noiseMeasure the residual noise level at each output terminal and confirm that measured value is -65 dBu or less.Note: Measure the noise level with the 22 Hz - 22 kHz band pass filter specified at 1-3.4. Inspection with analog test modeCondition:• Perform each test item in this section with the analog test mode of the test program. (See “TEST PROGRAM 4-15.ANALOG test”)• Unless otherwise specified, perform the test with an 8 Ω resistor connected to each output terminal.79