Electrical Checkout Procedures; Quiescent Ac Power Draw; Gain Switches; Y" Input Switch Operation - Crown K1 Service Manual

Rev A.

5.5 Electrical Checkout Procedures

The test procedures in this section are used to verify
the operation of the amplifier. You may, however, find
these tests helpful in troubleshooting a problem if the
problem is not easily identified.
All tests assume that AC power is from a regulated
source at the voltage the amplifier is set up for. See
Chapter 4 if you need to change the operating voltage.
Test equipment includes an oscilloscope, a DMM, a
signal generator, loads, watt meter, I.M. distortion ana-
lyzer, and a true THD meter.
During each test, it is assumed that the following con-
ditions are set on the amplifier unless otherwise noted:
—Level controls fully clockwise.
—Bridge Output switch off.
—"Y" Input switch off.
—Input Sensitivity of both channels set at 26 dB.

5.5.1 Quiescent AC Power Draw

Spec: 100 watts maximum quiescent. 10 watts in sleep
mode.
Procedure: With no load connected to the amplifier,
turn on the amplifier. Inject a small signal into one of
the inputs to keep the amplifier out of sleep mode.
Measure AC power draw. It should be less than 100
watts. Remove the signal from the amplifier and wait
approximately 6 seconds for the amp to go into sleep
mode. Measure AC power draw. It should be 10 watts
±3 W.

5.5.2 Gain Switches

Spec: 1.4 V, 26 dB
©1999 Crown International, Inc.
WARNING
Before unplugging or plugging in any connectors
or wires in the amplifier, discharge the power sup-
plies. See section 5.2.2 for instructions. Failure
to do so will result in circuit failure.
K1 Procedure: No Load. With the level controls at full
gain and the input sensitivity switches set to 1.4 V,
inject a 1 kHz, 0.775 Vrms, into each channel. At the
output of each channel measure 29.3 Vrms, ±0.9 Vrms.
Switch the Input Sensitivity switches to 26 dB. Mea-
sure 15.3 Vrms, ±0.6 Vrms, at the outputs.
K2 Procedure: No load. With the level controls at full
gain and the Input Sensitivity switches set to 1.4 V,
inject a 1 kHz, 0.775 Vrms, into each channel. At the
output of each channel measure 34 Vrms, ±1.3 Vrms.
Switch the Input Sensitivity switches to 26 dB. Mea-
sure 15.3 Vrms, ±0.6 Vrms, at the outputs.

5.5.3 "Y" Input Switch Operation

Spec: Channel 1 input will produce an output at both
channels. Both outputs will be in phase.
Procedure: No load. Switch the "Y" Input switch on.
Inject a 1 kHz sine wave into channel 1 only. You should
see output on both channels. They should be in phase
with each other. With the gain switches set the same,
and the level controls both at full volume, you should
see the same output voltage at both channels. Re-
move the signal and turn the "Y" Input switch off.

5.5.4 Bridge Mono Operation

Spec: Same voltage out both channels, channel 2 out
of phase.
Procedure: No load. Switch the Bridge Mono switch
on and inject a 1 kHz sine wave into channel 1 only.
Monitor both outputs of the amplifier. They should be
the same voltage and out of phase with each other.
Remove the signal and turn the Bridge Mono switch
off.
K Series Service Manual
Maintenance 5-9