Lexicon MPX G2 Service Manual page 30

MPX G2 Service Manual
3. Apply a 1kHz-sinewave signal at -11dBu (218 mVRMS).
4. Set the Analyzer to measure THD+N.
5. Verify an output THD+N reading is between 0.01 - 0.0001% at the following frequency settings.
20,000Hz
3,000Hz
6. Move the cable from the Left Insert Return jack to the Right Insert Return jack.
7. Move the cable from the Left Main Output jack to the Right Main Output Jack.
8. Verify an output THD+N reading is between (0.01 to 0.0001%) at the following frequency settings.
20,000Hz
3,000Hz
9. Set the Analyzer back to measure level.
Signal To Noise Ratio:
1. Apply a 1kHz-sinewave signal at -10dBu (245 mVRMS).
2. Set the Analyzer for a 0dB reference (@ 1kHz).
3. Turn off the oscillator.
4. Verify an output level reading between -82.94 to-120.00 dBu (55 to 0.8 uVRMS).
5. Move the cable from the Right Insert Return jack to the Left Insert Return jack.
6. Move the cable from the Right Main Output jack to the Left Main Output Jack.
7. Verify an output level reading between -82.94 to-120.00 dBu (55 to 0.8 uVRMS). Turn the oscillator
back on.
Insert Return Inputs to Outputs with Sum On:
The following test verifies the Inserts to Outputs with the Sum circuit engaged. The following parameters
must be set up before testing.
Setup/Test:
1. Press the System button then turn the knob CW to the end until the display reads: System Select
Development.
2. Press the Yes button 3 times. The display reads: Devel Sum Off 0. Turn the knob CW to On 1. This will
enable the Sum circuit.
3. Press the Yes button once. The display reads: Devel DSP R Sw Nrm10. Turn the knob CW to set the
left DSP to Loop 1.
4. Press the Yes button once. The display reads: Devel DSP L Sw Nrm10. Turn the knob CW to set the
left DSP to Loop 1.
5. Press the Yes button once. The display reads: Devel Mix Switch. Verify that Mix is set to Off 0.
6. Press the Yes button 4 times. The display reads: Devel SpkSp. Verify that Mix is set to Byp 0.
7. Press the Yes button 4 times. The display reads: Devel SpkrSim.BP. Verify that Mix is set to Byp 0.
8. Move the cable from the Left Insert Return jack to the Right Insert Return jack.
9. Apply a 1kHz-sinewave signal at -10dBu (245 mVRMS).
10. At the Left Main Output verify an output level reading between 27.06 to 24.94 dBu (17.5 to 14 Vrms).
Insert Return Inputs to Outputs with Split On:
The following test verifies the Inserts Return Inputs to Outputs with the Split circuit engaged. The following
parameters must be set up before testing.
Setup/Test:
1. Press the No button 11 times. The display reads: Devel Sum On 1. Turn the knob CCW to Off 0.
2. Press the No button 2 times. The display reads: Devel Split Off. Turn the knob CW to On this will
enable the Split switch. Note: The MPX G2 is already set for the proper input level from the last test.
4-18
15,000Hz 10,000Hz
997Hz 100Hz
15,000Hz 10,000Hz
997Hz 100Hz
5,000Hz
20Hz
5,000Hz
20Hz