Lexicon MPX G2, Service Manual

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MPX G2 Service Manual
4-16
Insert Return Inputs to Outputs:
The following tests will be testing the Insert Return to Output path as seen in the diagram below:
Insert Return Inputs to Outputs with Mix On:
The following tests verify the integrity of the Left/Right Insert Return Inputs to the Left/Right Main Outputs of
the MPX G2. As described in the above Input to Sends tests the MPX G2 must be setup with Program 250
Clean Slate loaded and the Development Row available in the System Menu. Once these are loaded the
following parameters must be set before testing.
Setup:
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 three times. The display reads: Devel Sum On 1. Turn the knob CCW to set the
Sum to Off.
3. Press the Yes button once. The display reads: Devel DSP R Sw. Verify that it is set for Nrm 10 (If not,
use the knob to change).
4. Press the Yes button once. The display reads: Devel DSP L Sw. Verify that it is set for Nrm 10 (If not,
use the knob to change).
5. Press the Yes button once. The display reads: Devel Mix Switch Off 0. Turn the knob CW to set this to
On 1.
6. Press the Yes button 8 times. The display reads: Devel SpkrSim BP On 1.Turn the knob CW to set this
to Byp 0.
7. On the Front panel, turn the Input Level Pot to Minimum (fully CCW).
8. Set the Output Level Pot to Maximum (fully CW).
9. On the back of the MPX G2 set the Insert Return Pot to 10 (fully CW).
10. Connect an audio input cable between the Low Distortion Oscillator and the MPX G2 Left Insert Return
jack.
11. Connect an audio output cable from the Left Main 1/4 Output jack on the rear of the MPX G2 to the
Distortion Analyzer.
Signal Level:
1. Apply a 1kHz-sinewave signal at -11dBu (218 mVRMS).
2. Verify an output level reading between 27.06 to 24.94 dBu (17.5 to 13.7 Vrms).
3. Move the cable from the Left Insert Return jack to the Right Insert Return jack.