Audio Fidelity Test - Alesis DEQ224 Service Manual

Rear Panel Sub Assembly Test CON'T

Audio Fidelity Test

1) Press the CHANNEL/EXIT and BYPASS buttons on the Known Good ME1 Front
Panel Sub-Assembly and hold these buttons during Step 2. When started
in this manner, the unit will enter Factory Test Mode.
2) Plug the P3 type Alesis Power Supply into a power source and the
barrel jack into the DUT Power In jack.
Verify that the front panel LEDs show normal power up message,
"DEQ224". After this message, "TEST" should display briefly on
the LEDs.
Problems with this inspection indicate that the unit has not
entered Factory Test Mode.
and 2.
3) When in Factory Test Mode, the unit will bypass audio so that AP
tests can run.
sequence. It is NOT necessary to enter a serial number since one has
not been assigned to the sub-assembly at this stage.
TESTS at the appropriate menu to run all AP tests. The menu system
should be self-explanatory and will guide the user through connection
checks. DISREGARD instructions to power-up the DUT, as the DUT has
already been powered, and is already in the correct Factory Test
Mode.
Verify that the tests run without displaying a "Test Failed"
message.
Problems with multiple test failures may be an indication of
faulty test connection.
found with the cabling.
correctly, then the DUT has FAILED.
Failure of this test indicates that this sub-assembly cannot
continue further testing.
Panel.
that the Front Panel may have been damaged, follow QC
procedures to check the Front Panel, because a faulty IC on the
DUT may have damaged the Known Good Front Panel.
4) Unplug the power supply to the DUT.
the DUT. This is the end of the Rear Panel Sub-Assembly electrical
test.
Press ENTER on the computer to start the test
Repeat the tests if a problem was
If all the cables have been connected
If any are hot, or if there is any other indication
Unplug the unit and repeat steps 1
Quickly check the ICs on the Front
Then unplug all other cabling to
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