Voltage Gain; Current Limit; Dc Offset; Differentiator Circuit - Crown Macro-Tech MA-2402 Service Manual

MA-2402 Service Manual
ODEP Voltage Chart
Tolerance ±0.1V
°C °F Voltage
35 95.0
34 93.2
33 91.4
32 89.6
31 87.8
30 86.0
29 84.2
28 82.4
27 80.6
26 78.8
25 77.0
24 75.2
23 73.4
22 71.6
21 69.8
20 68.0
19 66.2
18 64.4
17 62.6
16 60.8
15 59.0

5.3.4 DC Offset

Spec: 0 VDC, ±10 mV.
Procedure: Measure DC voltage at the output connec-
tors (rear panel). There is no adjustment for output off-
set. If spec is not met, there is an electrical malfunction.
Slightly out of spec measurement is usually due to U104/
U204 out of tolorance.
In
.047 uF
Figure 5.1 Differentiator Circuit
5-2 Maintenance
10.73
10.66
10.58
10.51
10.44
10.37
10.29
10.22
10.15
10.07
10.00
9.93
9.85
9.78
9.71
9.64
9.56
9.49
9.42
9.34
9.27
Out
1K Ohm

5.3.5 Quiescent Power Draw

Spec: 100 watts maximum
Procedure: With no input signal the amplifier should draw
no more than 100 watts from the power source. Slightly
high readings may be due to out of tolerance Output
Bias Adjustment.

5.3.6 Voltage Gain

Spec 26 dB Gain: Gain of 20.0 ±3%.
Spec 0.775V Sensitivity: ±10%.
Spec 1.4V Sensitivity: ±10%.
Procedure: No load connected. Inject a 0.775 VAC 1
kHz sine wave with the Sensitivity Switch in the 26 dB
position. Measure 15.5 VAC ±0.5 VAC at the amplifier
output. Inject a 0.775 VAC 1 kHz sine wave with the
Sensitivity Switch in the 0.775V position. Measure 64
VAC ±6 VAC at the amplifier output. Inject a 1.4 VAC 1
kHz sine wave with the Sensitivity Switch in the 1.4V
position. Measure 64 VAC ±6 VAC at the amplifier out-
put. Return the Sensitivity Switch to the 26 dB position.

5.3.7 Current Limit

Spec: 31.5 to 43.0 Amps
Procedure: Load the channel under test to 1 ohm. In-
ject a 1 kHz differentiated (10% duty cycle) square wave.
See Figure 5.1 for differentiator circuit. Increase output
level until current limit occurs. Current limit should oc-
cur between 31.5 and 43.0 amps (31.5 to 43.0 Vpk).
Observe clean (no oscillations) current clipping. See
Figure 5.2 for differentiated wave form at current limit.
Figure 5.2 Differentiated wave form at current limit
130445-1 Rev. A
©2000 Crown International, Inc.