Crown Macro-Tech MA-5002VZ Service Manual page 39

130446-1 Rev. A
Type of Test
or Adjustment
22. 1 kHz Power + THD
23. Functional
ODEP & VZ-ODEP
operation
©2000 Crown International, Inc.
Input Signal and
Load Parameters
1-kHz Sine Wave Note: Operation with a sine wave into a low imped-
Various Loads ance load, when operating at AC voltages of less than
200VAC, will cause the 30 A fuses to blow after 30 to
60 seconds. 30 A Fuse = Part Number A10285-30.
AC Mains of 120 VAC, 60 Hz; or 230/240 VAC, 50 Hz:
8-ohm Load: Minimum voltage is 102.0 Vrms
(1,300 W) with <0.1% THD.
4-ohm Load: Minimum voltage is 89.1 Vrms
(1,985 W) with <0.1% THD.
2-ohm Load: Minimum voltage is 70.7 Vrms
(2,500 W) with <0.1% THD.
AC Mains of 100-220 VAC, 50Hz:
8-ohm Load: Minimum voltage is 100.0 Vrms
(1,250 W) with <0.1% THD.
4-ohm Load: Minimum voltage is 86.3 Vrms
(1,865 W) with <0.1% THD.
2-ohm Load: Minimum voltage is 68.9 Vrms
(2,375 W) with <0.1% THD.
60-Hz Sine Wave For these tests, the cooling fan blade must be stopped.
2-ohm Load To stop the fans, turn off and unplug the amplifier. Lift
the fan wire connector from P729/P730 on the control
module. Turn the amplifier back on and perform these
tests. At the end of these tests, turn the amplifier off,
unplug it, and return the fan wires to the appropriate
position (P729 or P730).
Place the VZ mode switches in the AUTO position (see
Figure 5.4; remove top filter to access switches). With
a 2-ohm load per channel and output voltage of 60
Vrms 60 Hz to both channels, allow the heatsinks to
heat up until the ODEP protection circuit starts to limit
the output signal (this should take a few minutes). A
waveform like that shown in Figure 5.5 should be ob-
served. Note: In VZ AUTO mode the flattened portion
of the wave will probably not have the "clean" ap-
pearance of Figure 5.5, but should still resemble it.
Check to see that the IOC LED is lit and that the ODEP
LED dims and extinguishes when ODEP is activated.
While ODEP limiting is taking place, switch the VZ
mode switches to the VZ-ODEP position and verify
that the amplifier locks into low voltage mode (the
ODEP waveform should appear much more "clean").
MA-5002VZ Service Manual
Comments
Maintenance 5-11