Lexicon 200, Service Manual

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Lexicon
4-1
Chapter 4 Perfo r mance Verification
This section describes a quick verification of the operation of the MPX 200 and the integrity of its analog
and digital audio signal paths.
Initial Inspection
Inspect the unit for any obvious signs of physical damage. Verify that the front panel controls operate
smoothly and correctly. (Refer to the MPX 200 User Guide for detailed explanations of this functionality.)
Verify that all screws and rear panel jacks are secure.
Functional Tests
Initial Power On Check
1. The voltage selection switch on the MPX 200 should be checked prior to power-on. It is located on the
right side of the unit (facing the Front Panel). Make sure it is switched to the proper AC voltage setting
for your area.
2. Connect the power cord to the back of the MPX 200 and the other end into an isolated variable output
power supply (Variac).
3. Verify the Variac's AC voltage output is set to 0.
4. Set the MXP 200 power switch to the On position and slowly increase the AC voltage output of the
Variac to the proper voltage.
5. Verify the AC current draw is < .25 amps.
Normal Power Up
During normal power on, the MPX 200 will perform a series of diagnostic tests. These diagnostic tests
should take approximately 10 seconds. The diagnostic test sequence is displayed on the front panel LEDs
prior to the execution of the test wherever possible for troubleshooting purposes.
If there is a failure, the test number indication LED, shown in the table below, will remain lit indicating which
test has failed and the (Red) LEVEL LEDs will be lit indicating that a failure has occurred. Displaying the
Test/Error code on the LEDs before the test is executed makes it possible to determine which test failed if
the unit hangs or crashes during the test.
The following is a table of the test numbers, the test names and the diagnostic indicator LEDs.
Test # Test Name Diagnostic LED
1 ROM Checksum COMPRESSOR “–20dB”
2 SRAM COMPRESSOR “–10dB”
3 LEXICHIP3 WCS COMPRESSOR “
–
3dB”
4 LEXICHIP3 INT COMPRESSOR “Threshold”
6 EEPROM EFFECTS “Gate“
NOTE: The ROM, SRAM, LEXICHIP3 and CPU must be working properly in order for the Diagnostic LEDs
to operate correctly.
If the MPX 200 powers on without a diagnostic failure, the 7-segment display will read “200”, all of the front
panel LEDs will light in sequence from left to right, and the unit will enter normal operating mode.
Setup
1. Connect one end of the MIDI cable to the jack on the Rear Panel of the unit labeled "MIDI Out/Thru".
2. Connect the other end of the MIDI cable to the jack on the Rear Panel of the unit labeled "MIDI In".