CE 4000 Service Manual
Maintenance 4-8
130485-1 Rev. B
©2002 Crown Audio, Inc.
Figure 4.16 Required Test Equipment
fi lter. Readjust R178 and R278 for channel 1 and 2
respectively to get the frequency response in spec.
Troubleshoot and repair fi lter as necessary.
Amplifi er does not meet Voltage Gain specifi ca-
tion.
1. The gain of the amplifi er is determined by the BFG
PWA. Check the optocoupler for proper operation or
replace the BFG PWA.
2. Check residual resistance of gain level potentiom-
eters.
Amplifi er does not meet DC Output Offset speci-
fi cation.
1. Possible problem on the Main PWA, and is likely
a faulty U100/200 or a faulty MOSFET or diode
in the output stage. Troubleshoot and repair as
necessary.
2. Input PWA might be passing input signal DC
components. Check for short capacitors in the Input
PWA.
4.5 Required Test Equipment
Due to the complex circuitry utilized the CE 4000
amplifier, special calibration procedures and the
correct test equipment are necessary to insure
original factory specifi cations are achieved.
Figure 4.16 is list of test equipment needed to
successfully service the amplifi er. Recommended
models are those used by Crown.
Alternate oscilloscope choices: Tektronix TDS360 and HP HP54610B. The latter is a 500 MHz
scope, which is needed to test newer BCA power supplies.
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