Lexicon MC-1 Service Manual Download Page 29

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Lexicon

5-7

Diagnostic tests are selected by rotating the VOLUME knob, (front panel encoder), to display the desired
test, or group of tests, on the VFD. The

MUTE

button is then pressed to execute the test. The group tests

are those diagnostics where if a test passes, the diagnostic automatically executes the next test. The power
on diagnostics is a group test. The other group tests are the Pre Burn-In test, Functional Suite and the
Burn-In Loop. If one of the group tests is selected the next test is automatically run if the current test
passes. Upon successful completion of the group tests the VFD will either display DONE, come out of the
test group to the main menu or continuously loop as in the case of the Burn-In Loop test.

If a test fails, the VFD, and red VCR F.P. LED, will attempt to indicate the failed test. The test will attempt to
loop on itself to keep the signal lines active for debugging purposes. If an individual test is selected, it will
continuously run and report if it passes every time it successfully completes the test. If the test fails it will
attempt to loop on itself to keep the signal lines active for debugging purposes.

In addition, test progress and failure information is available via the serial debug port. Specific failure
information will depend on the test executed and is covered further in section 3.4 Error Log.

Pressing and holding the

BYPASS

F.P. button and then pressing the

MUTE

F.P. button returns the user to

the diagnostic menu. Pressing the

SHIFT/DONE

remote key combination returns the user to the top of the

EXTENDED DIAGNOSTICS menu.

Pre-Burn in Tests

The Pre-burn in tests are a group of tests that are almost identical to the Power On Diagnostic tests, but
with more allotted to fully evaluate functionality the Lexichip DRAM memory test. The following is the list of
tests performed:

1. Z80

CPU

Test.

2. EPROM

Checksum

Test.

3. Z80 SRAM Test (Destructive).
4. VFD

Test.

5.  Z80 System Interrupt Timer Test.
6.  Lexichip II/WCS Test.
7.  Lexichip II DRAM Test
8.  56004 SPI (Serial Peripheral Interface) Test.
9.  AC3 SPI, AC3 MEM or DTS AC3SPI, DTS AC3MEM Test.
10. DTS 56K Test.

Any of these tests can be run individually by turning the VOLUME knob to the desired test and pressing the
MUTE F.P. button to execute the test. If the test is selected to be individually run, the test runs
continuously. If the test passes, the VFD will attempt to report the test passes upon each successful
completion. If the test fails the VFD will attempt to report the failure and the test will continue looping on
itself to keep the signal lines active for debugging purposes.

Functional Suite

The Functional Suite is a group of tests that are used to verify the functionality of the switches, LED's,
VOLUME knob, VFD display, logo illumination, etc. The entire user interface is verified. They are not
executed during power on. The following is a list of the tests performed:

1. Character Test.
2. Block Test.
3. Switch Test.
4. LED Test.
5. AC3 SPI Test.
6. AC3 MEM Test
7. DTS AC3SPI Test
8. DTS AC3MEM Test