Crown k1 Manual Suplementario
K Series Service Manual
Rev A.
Maintenance 5-11
©1999 Crown International, Inc.
5.5.11 Post Test Settings
After completion of testing, if all tests are satisfactory, the
amplifier controls should be returned to the positions re-
quired by the customer. If the conditions are unknown or
unspecified, the factory settings are as follows:
–Gain switches set to 1.4 V
After completion of testing, if all tests are satisfactory, the
amplifier controls should be returned to the positions re-
quired by the customer. If the conditions are unknown or
unspecified, the factory settings are as follows:
–Gain switches set to 1.4 V
–Bridge Mono switch turned off
–“Y” Input switch turned off
–Level controls at 0 dB
–Power switch turned off
–“Y” Input switch turned off
–Level controls at 0 dB
–Power switch turned off
5.6 Calibrations
These calibrations should only be performed by those
servicers authorized to do component-level repair of
PWAs included in the module exchange program (see
Section 1.3).
servicers authorized to do component-level repair of
PWAs included in the module exchange program (see
Section 1.3).
5.6.1 Gaussian Filter Calibration
Procedure 1:
Obtain a multimeter with decibel mea-
surement capabilities.Set the multimeter to dB mea-
surement mode. Insert a 1Khz signal into the input
and measure at pin 8 of U103C. Reset the meter to
0dB using the 1KHz signal as a reference signal. In-
crease the signal generator frequency to 20KHz, leav-
ing the output level unchanged. While measuring pin 8
of U103C adjust R172 for a reduction of level by 2.6dB
(readout should be -2.6dB).
surement mode. Insert a 1Khz signal into the input
and measure at pin 8 of U103C. Reset the meter to
0dB using the 1KHz signal as a reference signal. In-
crease the signal generator frequency to 20KHz, leav-
ing the output level unchanged. While measuring pin 8
of U103C adjust R172 for a reduction of level by 2.6dB
(readout should be -2.6dB).
Procedure 2: Obtain a multimeter with decibel mea-
surement capabilities. Set the meter to dB measure-
ment mode. Insert a 1Khz signal into the input and
measure at the speaker output (no load). Reset the
meter to 0dB using the 1KHz signal as a reference
signal. Increase the signal generator frequency to
20KHz, leaving the output level unchanged. Adjust
R172 for a meter reading of 0db. This second test
method is an alternative to the first and should give
the desired results: a flat frequency response through-
out the audio bandwidth.
surement capabilities. Set the meter to dB measure-
ment mode. Insert a 1Khz signal into the input and
measure at the speaker output (no load). Reset the
meter to 0dB using the 1KHz signal as a reference
signal. Increase the signal generator frequency to
20KHz, leaving the output level unchanged. Adjust
R172 for a meter reading of 0db. This second test
method is an alternative to the first and should give
the desired results: a flat frequency response through-
out the audio bandwidth.
5.6.2 Overlap Correction and Adjustment
Conditions:
—Amplifier output assembly MUST be room tempera-
ture (72 degrees F/21 degrees C)
ture (72 degrees F/21 degrees C)
—No input signal
—No load
Procedure: Monitor TP51 found on the Output Assem-
bly. Center oscilloscope to view lower right portion of
waveform. Adjust R25 on each Output PWA for sharp-
est squarewave edges (see Figure 5.1). Figure 5.2
shows “Underlap” (under adjustment). Figure 5.3 shows
“Overlap” (over adjustment). If too much time is taken
bly. Center oscilloscope to view lower right portion of
waveform. Adjust R25 on each Output PWA for sharp-
est squarewave edges (see Figure 5.1). Figure 5.2
shows “Underlap” (under adjustment). Figure 5.3 shows
“Overlap” (over adjustment). If too much time is taken
Figure 5.1 Correct Overlap Adjustment
Figure 5.2 Underlap
Figure 5.3 Excessive Overlap
to perform this procedure the Sleep circuit may cause
the amplifier to go into standby. A brief input signal
(no load) will bring the amplifier out of Sleep mode.
the amplifier to go into standby. A brief input signal
(no load) will bring the amplifier out of Sleep mode.