Crown Macro-Tech 2402, Service Manual, Page: 23 / 90

Maintenance 5-3
130445-1 Rev. A MA-2402 Service Manual
©2000 Crown International, Inc.
.
5.3.8 10 kHz Square Wave Response
Spec: No overshoot, ringing, or oscillations. Slew rate
17 - 25 V/µS into 8 ohm load.
Procedure: Load the channel under test to 8 ohms. In-
ject a 10 kHz square wave to obtain 35 volts zero-to-
peak at the output. Observe the wave form. It must not
include overshoot (<23mV), ringing, or any type of os-
cillation. Rise time should be between 17 and 25 volts
per microsecond. See Figure 5.3 for typical 10 kHz
square wave response.
5.3.9 Crosstalk
Spec: 60 dB below 8 ohm rated power at 20 kHz, 85
dB below 8 ohm rated power at 1 kHz and below.
Initial Conditions: Per standard. Terminate input of chan-
nel not driven with 600 ohms.
Procedure: Load each channel to 8 ohms. Inject a 20
kHz sine wave into Channel 1 and increase the level to
63 VAC at the output. Measure less than 63 millivolts
AC at the output of Channel 2. Inject a 1 kHz sine wave
into Channel 1 and increase the level to 63 VAC at the
output. Measure less than 3.6 millivolts AC at the output
of Channel 2.Repeat for Channel 2 by driving channel
2 and terminating Channel 1. Measure less than 63 mil-
livolts at the output of Channel 1 at 20 kHz, and 3.6
millivolts at 1 kHz.
5.3.10 Output Power
North America:
Spec at 8 Ohm Stereo: >= 520W at 0.1% THD.
Spec at 4 Ohm Stereo: >= 800W at 0.1% THD.
Spec at 2 Ohm Stereo: >= 1050W at 0.1% THD.
International:
Spec at 8 Ohm Stereo: >= 512W at 0.1% THD.
Spec at 4 Ohm Stereo: >= 742W at 0.1% THD.
Spec at 2 Ohm Stereo: >= 924W at 0.1% THD.
Procedure:
North America: Load each channel to 8 ohms. Inject a
1 kHz sine wave and measure at least 64.50 VAC at the
output of each channel. Load each channel to 4 ohms.
Inject a 1 kHz sine wave and measure at least 56.57
VAC. Load each channel to 2 ohms. Inject a 1 kHz sine
wave and measure at least 45.82 VAC. All power mea-
surements must be at less than 0.1% THD.
International: Load each channel to 8 ohms. Inject a 1
kHz sine wave and measure at least 64.0 VAC at the
output of each channel. Load each channel to 4 ohms.
Inject a 1 kHz sine wave and measure at least 54.5
VAC. Load each channel to 2 ohms. Inject a 1 kHz sine
wave and measure at least 43.0 VAC. All power mea-
surements must be at less than 0.1% THD.
5.3.11 ODEP Limiting
Spec: Clean limiting into a resistive load (see Figure
5.4).
Procedure: Load each channel to 4 ohms. Inject a 50
Hz sine wave into each channel and increase the level
for 20 VAC at the output. Stuff a rag into the fan to pre-
vent the fan from turning. Observe the wave form on an
oscilloscope. After about 1 minute ODEP limiting will
occur (see Figure 5.4). Once limiting occurs the wave
form will collapse at a rapid rate. Make sure both chan-
nels limit. Remove the load and signal, remove the rag
from the fan, and allow the amp to cool.
Figure 5.3 10 kHz square wave response Figure 5.4 ODEP limiting wave form