Ecler MPA4-400, Service Manual, Page: 64 / 72

51-0098-0100 EP14-02 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 misfunction.
CAUTION: Do not disconnect nor touch the test probes until the test has finished
completely!
VERIFICATION USING MUSIC
- This unit is a four channel power amplifier, with a flexible input channel selection system,
which actually increases its range of use and connection applications. All input selection
stages and input combinations have been fully verified in the “CHECKING INPUT
SELECTION SWITCHES” section.
- Verify all inputs and outputs. Release all the input selection switches.
- Verify the input potentiometers sweeps, which should completely cut off the signal when
turned down, and should not produce any noise or scratching.
- Verify the unit’s sound quality, free from distortion and noise.
- Verify background noise in each channel.
- Check the low pass filters on channel 1, and the high pass filters on channels 3 and 4.
- Hit the unit several times against your working desk to ensure that there are no failing
contacts and defective junctions.
- While applying input signal, short the unit’s output contacts. Verify that when the
shorting is retired, the unit recovers its normal functioning status.
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.