Ecler MPA4-150 - Verification Process; Preliminary Checks; Output Verification

author: Queralt date: 000718
approved:
num:
51.0023 version: 01.00
VERIFICATION PROCESS
title:
EP05-99
E
C
LER
PRELIMINARY
- Check the Ground Link.
- Have a look at the unit's mains cable, inputs, outputs and other cables and
connectors.
- Check out that there are no shortings between the unit’s mounting frame, mains
carriers, and outputs.
- Set tested unit’s power main switch to Off position.
- While the signal generator is still turned off, adjust the generator’s output in order to
obtain a 1KHz 0dB output signal.
- Connect four 4Ω load impedances to outputs 1, 2, 3 and 4.
- Using a set formed by a mVoltmeter and a dual-channel oscilloscope, connect
oscilloscope’s channel one test probe between Output1 and signal ground, and connect
channel two’s test probe between Output2 and signal ground.
- Turn down both input trimming potentiometers to their minimum position.
- Connect the power amplifier to a 230Vac variac output.
- Set the following front-end selector switches to the positions as listed bellow:
- IN1/IN1+IN2 to IN1
- IN2/LINK IN1 to LINK IN1
- LP FILTER ON/OFF to OFF
- ST/B IN1/B IN1+IN2 to ST
- IN3/LINK IN1 to LINK IN1
- IN4/LINK IN2 to LINK IN2
- ST/BRIDGE to ST
- HP FILTER ON/OFF to OFF
VERIFICATION
- Switch the tested unit's Power main switch to ON. Verify that the power on LED is
lit.
- Set the signal generator to ON. At this point, all Signal Present LED's should light up.
- Turn up channel one's input triming potentiometer, and check that it's sweep is
complete and smooth. At its maximum position, check that Vo=20Vrms, and that the
output signal monitored on OUTPUT1 is only dependent from the INPUT1 signal.
- Turn up channel two's input triming potentiometer, and check that it's sweep is
complete and smooth. At its maximum position, check that Vo=20Vrms, and that the
output signal monitored on OUTPUT2 is only dependent from the INPUT2 signal.
- Both output signals should have no phase differs.
- Now change the ST/B IN1/B IN1+IN2 selector to the B IN1+IN2 position, and verify
that OUTPUT1 and OUTPUT2 phase differ has turned to push-pull. S.P. CHII's LED has
turned off, and the unit's channels 1&2 section is now controlled only by channel
one's input trimming potentiometer. Turn it up and leave it at its maximum position.
- Apply a 1KHz square wave signal. Moreover, shunt a 2µ2 capacitor to channel 1's 4Ω
output load. While monitoring the output signal on the osciloscope, vary the input
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