Lexicon LXP-5 Service Manual

Performance
Verification
Lexicon
Test Programs
LED test
(Bypass,)
Run AH Master tests
(Edit C;
requires a MIDI cable
Rotary Switch test
(Edit B;
Because the MasterRAMtest p assed, you can assume thatthe MasterRAM
(U17) is functioning properly, and the problem must be in the Slave RAM or
WCS. Slave RAM, Shared RAM, Slave WCS and Master WCS tests should
be performed.
1. If Shared RAM and Slave RAM tests both fail, the Slave RAM is suspect.
2. If Shared RAM test and Master WCS tests fail, the M aster/Slave interface
circuitry is suspect. Running further diagnostics which exercise the
Master Processor's access to the slave bus will verify this. ( S lave
Communications test, Slave Reset and Slave Interrupt)
3. If both Master and Slave WCS testefail, the Lexichip is probably faulty.
This test should cause the OVLD and LEARN LEDs to blink red in unison until
the next test selection. If it does not, check the OVLD or LEARN LED
hardware, the Master 280 or MIDI Serial circuitry, or the Lexichip.
If either the OVLD or the LEARN LED does not flash in this test, their
associated pulsed signals can be traced while the LED test is being run. Keep
in mind that these signals originate from different places. —the LEARN LED
signal originates at U5 pins 7 and 10; the OVLD LED signal originates from
pin 24 on the UART (U3).
This test is designed to save time by performing the following tests in
sequence:
ROM test
Master Address test
Master Interrupt test
MIDI Wraparound test
Run All Slave tests
DRAM test
This test requires a 5 pin DIN MIDI cable to be connected from the MIDI IN
jack to the MIDI OUT/THRU jack located at the rear of the unit. The MIDI OUT/
THRU switch should be set to its OUT position (toward the MIDI jacks).
The LEARN LED will flash a few times while this sequence of tests is running.
After approximately 30 seconds, the tests should be completed and the
results displayed. If ail tests pass, the LEARN LED will flash red. If any of the
tests fail, the LEARN and OVLD LEDs will alternately flash red. In the event
of a failure indication, each test in the sequence should be run individually to
determine which has failed.
This test compares the positions of the Function, Select and Adjust knobs.
When the positions match, the LEARN LED will be green. The LEARN LED
will be red when any one of these three knobs is in a different position than
the othertwo. Turn each knob to every position to complete this test. If the test
fails, knob hardware may be faulty.
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Lexicon LXP-5 Specifications

General

Brand	Lexicon
Model	LXP-5
Category	Recording Equipment
Language	English