Lexicon 200, Service Manual

Page: 21 / 90

Lexicon
5-1
Chapter 5 Trou b leshooting
Check the Lexicon web site for the latest software and information:
http://www.lexicon.com
The Lexicon Support Knowledgebase:
http://www.lexicon.com/kbase/index.asp
Diagnostics
Introduction
This section contains the complete diagnostics descriptions for the Lexicon MPX 200 product.
Diagnostics Test Descriptions
There are two categories of diagnostics that exist in the MPX 200 software: Power On Self Tests (POST),
and Extended Diagnostics. The POST are executed automatically when the system is first powered up. The
Extended Diagnostics are invoked by pressing and holding the front panel BYPASS button while powering
on the unit. The Extended Diagnostics are used to perform functional tests that are not performed during
the Power-On Self Tests, and also for troubleshooting purposes.
NOTE: The Extended Diagnostics can also be invoked by pressing and holding the Bypass Footswitch
(labeled Ring) while powering on the unit.
Power-On Self Tests (POST)
Upon normal power up, the MPX 200 will perform a series of diagnostic tests. For a description of these
tests, refer to Table 2.1. These diagnostic tests have been designed to take less than 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 (provided the LEDs are functioning properly).
Throughout this document, these LEDs will be referred to as the Diagnostic LEDs. These LEDs are used to
indicate the corresponding test number, and are turned on before each test is executed. 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.
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“
Table 2.1
NOTE: The ROM, SRAM, LEXICHIP3 and CPU must be working properly in order for the Diagnostic LEDs
to operate correctly.
Upon completion of the POST, the 7-segment displays will display “200”, all of the front panel LEDs will light
in sequence from left to right, then the unit will enter normal operating mode.
If a POST fails, the appropriate Diagnostic LED will remain lit indicating which test has failed and the (Red)
LEVEL LEDs are lit indicating a failure has occurred. If a failure has occurred, the unit should be repaired
before proceeding.