Ecler MPA4-150, Руководство по обслуживанию

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author:
Queralt
date:
000718
approved:
num:
51.0023
version:
01.00
VERIFICATION PROCESS
title:
EP05-99
ECLER
signal level until the output signal clips. At this point, a two- or three-cycled ripple
should appear on the flat sections of the square waveform. Repeat this same process
with channel two.
- Disconnect the oscilloscope's both channels test probes, and connect them to outputs
3-4.
- Turn up channel three'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 OUTPUT3 is only dependent from the INPUT3 signal.
- Turn up channel four'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 OUTPUT4 is only dependent from the INPUT4 signal.
- Both output signals should have no phase differs.
- Now change the ST/B IN1/B IN3+IN4 selector to the B IN3+IN4 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
three'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 3's 4
Ω
output load. While monitoring the output signal on the osciloscope, vary the input
signal level until the output signal clips. At this point, a two- or three-cycled ripple
should appear on the flat sections of the square waveform. Repeat this same process
with channel four.
- Set back the signal generator to its normal sine-wave operation mode.
- At this point, all clip indicators should be lighting. If necessary, add a little bit of level
to the input signal.
- Set the IN1/IN1+IN2 selector to IN1+IN2, and verify that the output level as
decreased 6dB.
- Return this switch to IN1.
- To verify the thermal protection circuits, short the thermal probe leads 1 and 2, and
verify that the relay releases and opens up, while the THERMAL LED indicator lights on
and the cooling fan increases its speed untill it reaches maximum airflow.
PROTECTIONS
- Disconnect the 4
Ω
load impedances.
- Switch the signal generator off, and select a 1V scale on it, while turning down and
leaving its output amplitude level potentiometer to minimum.
- Load the channel 1's output terminal with a 1
Ω
impedance.
- Turn on the signal generator, and increase its output amplitude level until the tested
unit's output signal starts to clip. At this oint, Vo=14Vpp.
- Decrease gradually the mains voltage using the variac, just until the unit's output
signal is no longer clipping.
- Then continue increasing smoothly the generator's output level, until the unit's output
level starts clipping again, which should occur when Vo=27'7Vpp. In both clipping
cases, however, the cliped signal should be clear and free of ringings and
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