51-0184-0100 EP08-06 MPA4-400R Anglès.doc 5 of 5
VERIFICATION USING MUSIC
Note: As this is a four-channel amplifier, with a versatile input signal selection system
which enhances its connectivity options, the previous procedures have checked that the
input circuitry selection options are functioning correctly when running with input
signals.
1. Release all of the input circuitry selector switches.
↑
2. Verify the outputs 1 and 2’s STACK function by testing their jack-type output connections.
3. Verify individually each of the inputs and their outputs.
4. Turn the amplifier off and on again with the main power switch.
5. Even when signal is applied onto the tested channel's input, while the unit is passing its
STANDBY run-up time, the speaker should remain quiet.
6. Verify the sweep of all potentiometers, which should turn easily and smoothly, without
producing noise or scratches.
7. Verify the sound quality (do not allow any kind of scratch or distortion)
8. Check the unit’s low pass filters on channels 1 and 2. f
c
=160Hz.
9. Check the unit’s high pass filters on channels 3 and 4. f
c
=160Hz.
10. To ensure that all electrical junctions are well-fixed, hit the tested unit softly against your
working table.
11.
Short the output terminals while carrying amplified signal, and verify that once the
short-circuit is removed, the unit recovers normal functioning.
12. Without input signal, and with the potentiometers turned all down first, and also turning them
up to maximum level, verify that the unit’s output signal is free of hum and noise when
listening the output signal through loudspeakers.
QUALITY CONTROL
All mechanical parts should be visually revised, in order to detect scratches on the unit's
painting; all screws should be on their place, correctly tight and unmarked. Check out the unit's
general presentation.
