51-0191-0100 EP04-06 MPA4-80R Anglès.doc 4 of 4
Electrical insulation test:
Connect the electrical insulation tester probes between the mains outlet ground contact
and both shorted mains input poles. Adjust the tester’s current limit down to 10mA. Apply
1500Vac during 5 seconds.
The unit’s insulation should be able to resist this voltage, without generating spurious
sparks or a sparkover effect, and the tester may not detect any disfunction.
CAUTION: Do not disconnect nor touch the test probes until the test has finished completely!
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.
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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. Verify the sweep of all potentiometers, which should turn easily and smoothly, without
producing noise or scratches.
5. Verify the sound quality (do not allow any kind of scratch or distortion)
6. To ensure that all electrical junctions are well-fixed, hit the tested unit softly against your
working table.
7. Short the output terminals while carrying amplified signal, and verify that once the
short-circuit is removed, the unit recovers normal functioning.
8. 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.
