51-0191-0100 EP04-06 MPA4-80R Anglès.doc 2 of 4
VERIFICATION:
1. Turn the tested unit's main power switch ON.
2. Increase gradually the variac's output, until reaching 230V mains voltage. While increasing,
observe carefully the unit, in order to detect any malfunction (heavy vibrations on the
transformer, DC voltage on the amplifier module output, etc.)
3. Check that the red neon is lit.
4. Turn on the signal generator.
5. Verify that all the SIGNAL PRESENT LED’s are also lit.
6. Turn up channel one's input potentiometer. Check that it turns easily and smoothly. At its
maximum position, check that Vo=14Vrms
7. The output signal monitored on OUTPUT1 should be only dependent from the channel 1’s
input signal.
8. Turn up channel two's input potentiometer. Check that it turns easily and smoothly. At its
maximum position, check that Vo=14Vrms
9. The output signal monitored on OUTPUT2 should be only dependent from the channel 2’s
input signal.
10. Both output signals should be in identical phase.
11. Now change the STEREO / BRIDGE channel 1 & 2 selector to BRIDGE position
12. OUTPUT1 and OUTPUT2 should now have opposite phase.
13. Channel 2’s Signal Present indicating LED turns off.
14. The unit's gain level is now controlled only by channel one's input potentiometer. Turn it up
and leave it at its maximum position.
15. Now connect the millivoltmeter and oscilloscope probes to the amplifier’s outputs 3 and 4.
16. Turn up channel three's input potentiometer. Check that it turns easily and smoothly. At its
maximum position, check that Vo=14Vrms
17. The output signal monitored on the output should be only dependent from the channel 3’s
input signal.
18. Turn up channel four's input potentiometer. Check that it turns easily and smoothly. At its
maximum position, check that Vo=14Vrms
19. The output signal monitored on the output should be only dependent from the channel 4’s
input signal.
20. Both output signals should be in identical phase.
21. Now change the STEREO / BRIDGE cannel 3 & 4 selector to BRIDGE position.
22. OUTPUT3 and OUTPUT4 should now have opposite phase.
23. Channel 4’s Signal Present indicating LED turns off.
24. The unit's gain level is now controlled only by channel three's input potentiometer. Turn it up
and leave it at its maximum position.
25. At this point, all clip indicators should be lighting. If necessary, add a little bit of level to the
input signal.
26. Set the IN1/IN1+IN2 selector to IN1+IN2, and verify that the output signal level drops 6dB on
all outputs.
27. Return the switch back to IN1.
