Extended Diagnostics - Lexicon MPX 500 Service Manual

when the test is executed. If the stored value read from the first five bytes of the EEPROM is incorrect, the
EEPROM will be initialized.
Second, the test will read each byte in the User Register portion of the EEPROM and add them together to
calculate a checksum. This value is compared with the checksum value stored in the EEPROM itself. This
checksum will be recalculated each time a register is stored.

Extended Diagnostics

Extended Diagnostics are provided to help in troubleshooting specific functions in the MPX 500.
To enter the Extended Diagnostics, power on the unit while pressing down & holding the BYPASS button
on the front panel of the MPX 500. When the EDIT LED is lit, the BYPASS button can be released. After it
is released, the EDIT LED will go out and the LCD Display will indicate the test number and it name. The
Binary testcode will be displayed on the front panel (Bypass, Store, and Tap LEDs) as was described in the
Power Up Diagnostics section earlier in this chapter.
The following is a complete list of tests in the Extended Diagnostics.
ROM Test
SRAM Test
WCS Test
INT Test
ADF Test
EEPROM Test
DRAM Test
Switch Test
Encoder Test
MIDI Test
LCD Test
Exit Test
Init
Burn In Test
When each of these tests are run, they will display the test code and report an error the same way the
Power Up Diagnostic did. Unlike the power Up diagnostics however, each can be chosen individually by
turning the PROGRAM knob. Once a test is selected, execution of the test is done by pressing the Program
knob.
Lexicon
5-3