Rom Test; Sram Test - Lexicon MPX 500 Service Manual

MPX 500 Service Manual
The table below displays each Extended Diagnostic test and the code the front panel will display before the
tests are executed:
Test Test
Number Name
x
1 ROM
x
2 SRAM
x
3 WCS
x
4 INT
x
5 ADF
x
6 EEPROM
z
7 DRAM
y
8 Switch
z
Encoder
9
z
10 MIDI
y
11 LCD
12 Exit
13 Init
14 Unused
15 Unused
z
16 Burn In
x
These tests reside in the Power Up Diagnostics.
y
Requires operator interaction and judgment. Doesn't generate an error message.
z
Requires operator interaction and judgment. Generates an error message.
0 = OFF
1 = ON
To execute each of the following tests, the BANK button must be pressed (PROGRAM knob).
The lower left side of the LCD will display the word Running ... indicating that the test is working.
After the test has run its course, a Pass/Fail message will replace the Running... message indicating the
results of the test.
The EDIT LED will light if the test Passes.
The LOAD LED will light if the test Fails.
Tests 1 to 11 can be run continuously by pressing the TAP button instead of the BANK button (PROGRAM
knob) when executing the test.

#1 ROM Test :

The ROM checksum, which is a byte size value is located in the last location of each Bank. The test adds
the contents of the entire ROM including the check sum byte. The result should equal a 0 for the test to
pass.

#2 SRAM Test:

This test will verify the entire contents of the SRAM with the exception of the stack area which is tested by
the power-up SRAM test. The test first writes 00hex (000000000 binary) to all of the memory locations, and
then verifies this by reading back all the memory locations. The test will also write/read the following
patterns: 55hex (01010101 binary), AAhex (10101010 binary), and FFhex (11111111 binary).
5-4
BYPAS STORE
S LED
LED
0 0
0 1
0 1
1 0
1 0
1 1
1 1
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
TAP LCD
LED Display
1 ROM
0 SRAM
1 WCS
0 INT
1 ADF
0 EEPROM
1 DRAM
0 Switch
0 Encode
0 MIDI
0 LCD
0 Exit
0 Init
0 Unused
0 Unused
0 BurnIn