Bridge Mono - Crown CE-1000A Service Manual

Rev. D
Type of Test
or Adjustment

6. Bridge Mono

7. LED Check
8. Current Limit
9. 10-kHz Square Wave
Slew Rate Test
CE Series Service Manual
Input Signal and
Load Parameters
1-kHz Sine Wave
No Load
No Input
No Load
1-kHz Sine Wave
10-kHz Sq. Wave
8-ohm Load
Fig. 2.3 Bridge MONO
Comments
Note: Always turn power to the amplifier off prior to
changing the position of the Mode Switch. With the
dual/mono switch in the bridge mono position, insert a
0.775 Vrms 1-kHz signal into channel one input. There
should be signal present on both channel outputs,
equal in amplitude, with channel two 180 degrees out
of polarity from channel one (see Fig. 2.3). Channel
one input level control should control the output level
for both channels. Return the amplifier to stereo opera-
tion.
Turn the amplifier on after being off at least 10 sec-
onds. Make sure the green Power LED is on. If not,
check the ground screw at the front of the amplifier,
near C218, that holds the PWB to the chassis. Also
suspect R4, E1, or R19.
Set the sensitivity switch to 26-dB and check that both
level controls are fully clockwise. Insert a 3.5V 1-kHz
sine wave into channel 1 only and capture the output
signal on a digital storage scope. Turn off the signal.
The limits for the CE 1000 are 20 A ±5 A. For the CE
2000 the limits are 25.5 A ±5.5 A. Change the input
signal to channel 2 only and repeat the test.
With an 8-ohm load on each channel, insert a 10-kHz
square wave and adjust amplitude to produce an out-
put 10V below clipping. Observe a 7V/µS (or higher)
slew rate. The output waveform should be stable with
no ringing or over-shoot.
Maintenance 2-6