51-0184-0100 EP08-06 MPA4-400R Anglès.doc 3 of 5
CHECKING INPUT SELECTION SWITCHES.
SWITCH POSITION
IN1/IN1+IN2 IN1
IN2/LINK CH1
LINK CH1
LP FILTER ON/OFF
OFF
STEREO / BRIDGE IN1 / BRIDGE IN1+IN2
STEREO
IN3/LINK CH1
LINK CH1
IN4/LINK CH2
LINK CH2
HP FILTER ON/OFF
OFF
STEREO / BRIDGE IN3 / BRIDGE IN3+IN4
STEREO
0dBV 1KHz input signal to IN1
Millivoltmeter/oscilloscope connected to channel 1 and 2.
- Channel 1’s Signal Present indicating LED lights up. Turn up channel one’s potentiometer.
Verify its sweep. Vo=41V
rms
. Check that the output corresponds to the used channel.
- Channel 2’s Signal Present indicating LED lights up. Turn up channel two’s potentiometer.
Verify its sweep. Vo=41V
rms
. Check that the output corresponds to the used channel.
- Both outputs are in phase.
- On the channel’s STEREO/BRIDGE IN1/BRIDGE IN1+IN2 switch, select BRIDGE IN1+IN2.
By now both outputs should be push-pull configured. The SP 2 indicating LED turns off. Verify
that now only channel one’s input potentiometer is active, and leave it up to its maximum
position.
- On the IN1/IN1+IN2 switch, select IN1+IN2. Check that the output level has dropped 6dB.
- Leave the switch again to IN1.
- Change the millivoltmeter/oscilloscope test probes from the actual outputs to outputs 3-4.
- Verify that channel 3’s Signal Present indicating LED is lit. Turn up channel 3’s input
potentiometer. Verify it’s sweep. Vo=41V
rms
. Check that the output corresponds to the used
channel.
- Verify that channel 4’s signal present indicating LED is lit. Turn up channel 4’s input
potentiometer. Verify it’s sweep. Vo=41V
rms
. Check that the output corresponds to the used
channel.
- Both outputs are in phase.
