Ecler PAM1400, Service Manual

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FREQUENCY RESPONSE
0.5V input signal.
Verify frequency response at 20Hz/2kHz/20kHz. We must get the same signal output for the actual load
at any of the frequencies. Set the frequency at 50kHz; the output level should not decrease more than 1 or 2 dB
and there should not be any noticeable distortion.
CLIPPING AT 1kHz
Introduce such a signal that the amplifier is just about to clip. Measure the voltage up at the output (with
the actual load) and check that when the voltage decreases between 0.5 and 1 dB the clipping LEDs light down.
Check each LED corresponds to its fader.
DC OUT
For this test you must disconnect the load from the amplifier.
Introduce a 1V signal at
#
5Hz with the generator. Turn the output of the generator up until the protection
relays open and close.
MONO-STEREO
Make this test with a load of 8 Ω connected between left and right channels' terminals.
Set the MONO-STEREO switch in MONO. Verify that the fader of channel 1 is operating while channel 2
is NOT operating. Verify that the MONO LED is lighten up. Check the signal cut over the load is clean. Set the
amplifier back to STEREO mode.
PROTECTIONS
Disconnect the amplifier from the load and introduce with the signal generator a level of approximately
100mV RMS at 1KHz. Leave the attenuators at 0dB and shortcircuit the left channel output (just for a while)
checking the PROTECT LED is lighting up and the relay opens the circuit (you can check this by placinf an
oscilloscope probe at the amplifier's output and watching the signal disappear during the STAND BY time in which
the protection circuit is working).Repeat the same process for the right channel.
Set the amplifier in MONO mode in the same way as previously. Shortcircuit both channel output
terminals (L and R) (just for a while).Any of both channels must go into protect mode, lighting the corresponding
LED and making the relay open the circuit.