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MPA4-400 SERVICE MANUAL A 4- CHANNEL 1 CHANNEL 2 CHANNEL 3 CHANNEL 4 MULTICHANNEL POWER AMPLIFIER POWER CHANNEL 2 CHANNEL 1 BRIDGE IN 1 STEREO OUTPUT MAINS INPUT LP FILTER IN 2 IN 1 BRIDGED BRIDGED BRIDGE IN 1+IN 2...
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SERVICE MANUAL MPA4-400 INDEX - BLOCK DIAGRAM - FUNCTIONING DESCRIPTION - SCHEMATICS Power amplifier Inputs Power Supply + Outs Leds + potentiometers - COMPONENTS LOCATION SCHEMA Power amplifier Power Supply + Inputs + Outs Leds + potentiometers - TESTING AND QUALITY CONTROL...
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Queralt 020927 EP14-02 MPA4-400 ECLER author: date: project: product: approved: title: FUNCTIONING DESCRIPTION 52..0017 01.00 num: version: The amplifying stage basic structure is actually the one commonly used until now, this is, a push-pull mounted A-B class amplifier, using P-type (IRFP9240) and N-type (IRFP240) mosfets.
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Moreover, as the helper-transistor's base-emitter current is temperature-dependent, the controlling circuitry (basically the control-transistor) compensates the safe operation area (SOA) drift due to temperature. If the MOSFET's drain-source voltage (Vds) drops too low, a second circuitry actuates to alter the control-transistor's triggering level, obtaining a SOA-like curve section and a current stage, which can be adjusted adequately in order to maintain the MOSFET's power consumption as close as possible to its SOA.
J. Colomines 021007 EP14-02 MPA4-400 ECLER author: date: project: product: approved: title: VERIFICATION PROCESS 51.0098 01.00 num: version: PRELIMINARY: - Check the Ground Link switch. - Be sure that the correct cable types are used. - Main POWER switch OFF.
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- Connect a load impedance formed by a 4Ω resistor shunted to a 1µ5F capacitor, and apply a 1KHz square waveform input signal. Using an oscilloscope, observe the output signal, at the flat level areas of the squared waveform, only two or three ringings should be detected both at positive and negative slope flanges.
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- Channel 1’s Signal Present indicating LED lights up. Turn up channel one’s potentiometer. Verify its sweep. Vo=41V . Check that the output corresponds to the used channel. - Channel 2’s Signal Present indicating LED lights up. Turn up channel two’s potentiometer.
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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.
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