Alesis DEQ830 Service Manual page 23

Rear Panel Sub Assembly Test – DIGITAL CON'T
5) Press PROGRAM. This runs the MIDI test.
Verify that the front panel LEDs shows test "MIDI" for 1
second.
Verify that display shows "MIDI PASS".
Problems with this inspection indicate that there is a MIDI
electrical or cabling problem.
MIDI Cable, unplug the IEC Cable and repeat steps 1 through 5.
If the error message still shows after adjusting the cable,
then the DUT has FAILED.
Failure of this test indicates that this sub-assembly cannot
continue further testing.
6) Press PROGRAM once to advance to the audio ("A.") test.
7) Connect one end of the ADAT Optical cable from DUT Optical OUT to DUT
Optical IN.
Verify that the source indicator in the middle of the front
panel shows the audio switching from "ANALOG" to "DIGITAL", and
that the "DIGITAL" indicator stays lit solid.
Problems with this inspection indicate that there is a optical
audio problem.
Cable, unplug the IEC Cable and repeat steps 1 through 6.
Also, verify that the Known Good Front Panel has been properly
RESET as described in Section 7 "RESET".
Front Panel and adjusting the loopback cable, the unit does not
switch to "DIGITAL" then there is a problem with ADAT Optical
and the DUT has FAILED.
Failure of this test indicates that this sub-assembly cannot
continue further testing.
8) Press PROGRAM once to continue to the DIG AUDIO test.
audio test will be performed later.
Verify that the front panel LEDs shows test messages:
MIDI -> A. -> DIG A.
Stop here.
Verify that the front panel LEDs shows test "DIG A." for 1
second.
Verify that display shows "DIG PASS".
Problems with this inspection indicate that there is a ADAT
Optical electrical or cabling problem.
replacing the ADAT Optical Cable, unplug the IEC Cable and
repeat steps 1 through 6.
after adjusting the cable, then the DUT has FAILED.
Try adjusting or replacing the
Try adjusting or replacing the ADAT Optical
If the error message still shows
If after reseting the
The analog
Try adjusting or