Lexicon MC-1 Service Manual Download Page 15

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4-3

8.  Use the output level from Step 4 above for a 0dB reference to check frequency response.
9.  Turn the filter off. Next sweep the oscillator frequency from 10Hz to 20kHz.
10.  Verify that the signal level is 0.2/-0.3dB of reference level over the frequency band.
11.  Set the scale on the Distortion Analyzer to measure –90dBr signal level with the filter on. Turn off the

oscillator to the MC-1 and verify a noise level measurement less than -100dBr.

12.  Swap the cables from the Left VCR input to the Right and the Left RECORD output to the Right.
13.  Repeat steps 1 to 11 above for the Right RECORD output.
14.  To test the remaining inputs of the MC-1 to the RECORD outputs each path must be set with the

remote control. Press and hold the RECORD button, then press one of the analog input buttons to set
up the next input to RECORD output path. Below are the verification #’s next to their button titles that
indicate the path has been enabled. After a new input is selected the procedure above needs to be
repeated to test the path.

RECORD, VCR: 53

RECORED, DVD: 52

RECORD, V-DISC: 51

RECORD, TV: 50

RECORD, AUX: 4F

RECORD, CD: 4E

RECORD, TUNER: 4D

RECORD, TAPE: 4C

Input to Zone 2 Output Test

Setup

1. Attach the audio input cable between the Low Distortion Oscillator and the MC-1 Left VCR input.
2. Attach the audio output cable between the MC-1 Zone 2 output and the input of the Distortion

Analyzer.

3. Put the MC-1 into Extended Diagnostics mode by powering up the MC-1 while pressing and holding

down both the front panel REC/ZONE2 and EFFECT buttons until Extended Diagnostics appears on
the display.

4. Press the TAPE button on the remote. The display will read AUDIO Test.
5. Press and hold the Shift button on the remote, then press the Off button. The #99 will then be displayed

next to AUDIO Test.

6. Press and hold the RECORD button on the remote then the VCR button. The # 53 will then be

displayed. This confirms the VCR input is now set to the ZONE 2 outputs.

Tests

1.  Apply a 1kHz signal @ +12dB (+4 Vrms) to the input channel.
2.  Set the scale on the Distortion Analyzer to m12dBV (+ 4Vrms ) signal level.
3.  Turn all filters off on the Analyzer.
4.  Verify that the output level from the MC-1 is +12dBV ( +4Vrms ) +0.2/-0.3dBV.
5.  Adjust the scale on the Distortion Analyzer to measure 0.005% THD+N and turn on the 30kHz low

pass or audio bandpass filter.

6.  Verify that the THD+N measured is less than 0.005%
7.  Use the output level from Step 4 above for a 0dB reference to check frequency response.
8.  Set the scale on the Distortion Analyzer to m12dBV (+ 4Vrms) signal level.
9.  Turn the filter off and sweep the oscillator frequency from 10Hz to 20kHz.
10.  Verify that the signal level is 0.2/-0.3dB of reference level over the frequency band.
11.  Set the scale on the Distortion Analyzer to measure –100dBr signal level with the filter on. Turn off the

oscillator to the MC-1 and verify a noise level measurement less than -105dBr.

12.  Swap the cables from the Left VCR input to the Right and the Left ZONE 2 output to the Right.
13.  Repeat steps 1 to 11 above for the Right ZONE 2 output.
14.  To test the remaining inputs of the MC-1 to the ZONE 2 outputs, each path must be set with the

remote control. Press and hold the ZONE 2 button, then press one of the analog input buttons to set
up the next input to ZONE 2 output path. Below are the verification #’s next to their button titles that
indicate the path has been enabled. After a new input is selected the procedure above needs to be
repeated to test the path.