Crown ct-1600 Manual Suplementario
Com-Tech 200 Amplifier Service Manual
13
77
25.0
–10.00
10.00
78
25.6
–9.97
9.97
80
26.7
–9.91
9.91
82
27.8
–9.86
9.86
84
28.9
–9.80
9.80
86
30.0
–9.74
9.74
88
31.1
–9.69
9.69
90
32.2
–9.63
9.63
92
33.3
–9.57
9.57
94
34.4
–9.51
9.51
–ODEP Procedure: Measure pin 3 of J500 and, if neces-
sary, adjust R121 to obtain V
–ODEP
as specified above.
Measure pin 3 of J500 and, if necessary, adjust R221
to obtain V
to obtain V
–ODEP
as specified above.
+ODEP Procedure: Measure pin 4 of J500 and, if neces-
sary, adjust R132 to obtain V
+ODEP
as specified above.
Measure pin 4 of J500 and, if necessary, adjust R232
to obtain V
to obtain V
+ODEP
as specified above.
Test 4: AC Power Draw
Spec: 60 Watts maximum quiescent.
Initial Conditions: Controls per standard.
Procedure: With no input signal and no load, measure
AC line wattage draw. If current draw is excessive,
check for high AC line voltage or high bias voltage.
check for high AC line voltage or high bias voltage.
Test 5: Common Mode Rejection
Spec at 100 Hz: –70 dB.
Spec at 20 kHz: –50 dB.
Initial Conditions: Controls per standard.
Procedure: No load. Inject a 0 dBu (.775VRMS) 100 Hz
sine wave into each channel, one channel at a time,
with inverting and non-inverting inputs shorted to-
gether. At the output measure less than –44 dBu
(4.9mVRMS). Inject a 0 dBu 20 kHz sine wave into each
channel, one channel at a time, with inverting and non-
inverting inputs shorted together. At the output mea-
sure less than –24 dBu (49mVRMS). For Main Modules
with board numbers lower than D 7993-5 adjust N100
and N200 to calibrate CMR. For Main Modules with
board number D 7993-5 or greater adjust R921 and
R1021.
with inverting and non-inverting inputs shorted to-
gether. At the output measure less than –44 dBu
(4.9mVRMS). Inject a 0 dBu 20 kHz sine wave into each
channel, one channel at a time, with inverting and non-
inverting inputs shorted together. At the output mea-
sure less than –24 dBu (49mVRMS). For Main Modules
with board numbers lower than D 7993-5 adjust N100
and N200 to calibrate CMR. For Main Modules with
board number D 7993-5 or greater adjust R921 and
R1021.
Test 6: Voltage Gain
Spec 26dB Gain: Gain of 20.0 ±3%.
Spec 0.775V 8/4 ohm Sensitivity: ±6%.
Spec 0.775V 70-V Sensitivity: ±6%.
Initial Conditions: Controls per standard.
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
position. Measure 15.5 VAC ±0.5 VAC at the amplifier
Electrical Checkout Procedures
output. Inject a 0.775 VAC 1 kHz sine wave with the
Sensitivity Switch in the 0.775V 8/4 ohm position.
Measure 28.9 VAC ±1.7 VAC at the amplifier output.
Inject a 0.775 VAC 1 kHz sine wave with the Sensitivity
Switch in the 0.775 VAC 70-V position and the Output
Mode Switch in the 70-V position. Measure 70.7 VAC
±4.2 VAC at the amplifier output. Return the Sensitivity
Switch to the 26 dB position. Return the Output Mode
Switches to the 8/4 ohm position.
Sensitivity Switch in the 0.775V 8/4 ohm position.
Measure 28.9 VAC ±1.7 VAC at the amplifier output.
Inject a 0.775 VAC 1 kHz sine wave with the Sensitivity
Switch in the 0.775 VAC 70-V position and the Output
Mode Switch in the 70-V position. Measure 70.7 VAC
±4.2 VAC at the amplifier output. Return the Sensitivity
Switch to the 26 dB position. Return the Output Mode
Switches to the 8/4 ohm position.
Test 7: Phase Response
Spec: ±10° from 10 Hz to 20 kHz at 1 Watt.
Initial Conditions: Controls per standard, 8 ohm load on
each channel.
Procedure: Inject a 1 kHz sine wave and adjust for 1 watt
Procedure: Inject a 1 kHz sine wave and adjust for 1 watt
output (2.8 VAC). Check input and output signals
against each other, input and output signals must be
within 10° of each other.
against each other, input and output signals must be
within 10° of each other.
Test 8: Level Controls
Spec: Level controlled by level controls.
Initial Conditions: Controls per standard.
Procedure: No load. Inject a 1 kHz sine wave. With level
controls fully clockwise you should see full gain. As
controls are rotated counterclockwise, observe similar
gain reduction in each channel. When complete, return
level controls to fully clockwise position.
controls are rotated counterclockwise, observe similar
gain reduction in each channel. When complete, return
level controls to fully clockwise position.
Test 9: Current Limit
Spec: Current Limit at 13 Amps, ±2 Amps.
Initial Conditions: Controls per standard.
Procedure: Load each channel to 1 ohm. Inject a 1 kHz
differentiated (or 10% duty cycle) square wave. See
figure 4. Increase output level until current limit occurs.
Current limit should occur at 13 ±2 Amps (13 Vpk).
Observe clean (no oscillations) current clipping.
figure 4. Increase output level until current limit occurs.
Current limit should occur at 13 ±2 Amps (13 Vpk).
Observe clean (no oscillations) current clipping.
Figure 4. Differentiator Circuit
In
Out
.047 uF
1K Ohm