Cambridge Audio CXA61, Руководство пользователя

Страница: 12 / 14

CAP5 - Five way protection system
Cambridge Audio has developed a proprietary protection system to ensure
reliability and a long life for its amplifiers and the speakers they are
connected to. This protection system comprises of five main protection
methods:
1. DC DETECTION
Indication - Unit has switched off during operation. The front panel LED
light flashes together in the following sequence, one flash with long pause
between flashes. Read below for more information.
Description - CAP5 offers loudspeaker protection if the output of the
amplifier goes to a high constant voltage (DC) because of some internal
fault. This is a rare fault although detecting it could just save those
expensive loudspeakers.
Remedy - Due to the necessary sensitivity of the DC protection circuit,
extremely hard clipping of the amplifier may cause DC protection to be
triggered. If this fault occurs, please contact your dealer for service.
2. OVER TEMPERATURE DETECTION
Indication - Unit has switched off during operation. The front panel LED
light flashes together in the following sequence, two quick flashes with
long pause between flashes. Read below for more information.
Description - Over temperature is caused by a combination of high
listening levels and low impedance speakers. CAP5 includes temperature
detection which constantly monitors the heat generated by the output
transistors. If the monitored temperature reaches a high level (suitably
within the limits of the output devices) the amplifier will automatically
switch into a fault mode. The unit should ideally be left for 15 minutes in
this state to cool down adequately. If the unit has not fully cooled down
then the temperature may reach the limit soon after the amplifier is
powered up. If the loudspeaker impedance is low the temperature of the
amplifier may rise faster as the amplifier is working harder. If the amplifier
is mounted in a cabinet or the ventilation slots are obstructed the over
temperature detection may activate/reactivate after a short listening time.
Remedy - The internal temperature of the output transistors has reached
the over temperature limit. Leave the unit for 15 minutes to cool down
before pressing the Standby button to resume normal operation.
3. OVERVOLTAGE/OVERCURRENT DETECTION
Indication - Unit has switched off during operation. The front panel LED
light flashes together in the following sequence, three quick flashes with
long pause between flashes. Read below for more information.
Description - CAP5 offers V/I (voltage/current) protection by constantly
monitoring the output transistors to keep them working inside their
Safe Operating Area (SOA). The SOA is a set of limits given by the output
transistor manufacturer to ensure reliability. The V/I protection has been
incorporated within the amplifier circuitry to provide a fast response to
temporary overload conditions. When the V/I protection is triggered
the unit will continue to operate but distortion may be heard as the unit
protects the output transistors.
Remedy - Reduce the volume. If distortion is still present, check the
speaker connections and ratings.
4. SHORT CIRCUIT DETECTION
Indication - Unit has switched off during power up. The front panel LED
light flashes together in the following sequence, four quick flashes with
long pause between flashes. Read below for more information.
Description - During power up from Standby CAP5 performs a check on
the loudspeaker terminals to see if a short across the terminals has been
accidentally introduced. If the resistance measured across the loudspeaker
terminals is too low the unit will stay in Standby mode until the fault has
been removed and Power up is re-attempted.
Remedy - There may be a short circuit between the loudspeaker terminals.
Check all loudspeaker connections before attempting to switch the unit
out of Standby.
Troubleshooting
THERE IS NO POWER
Ensure the AC power cord is connected securely.
Ensure the plug is fully inserted into the wall socket and is switched on.
Check fuse in the mains plug or adaptor.
THERE IS NO SOUND
Make sure the unit is not in Standby mode.
Check that source component is properly connected.
Check that your speakers are properly connected.
Make sure the selected speaker A/B light corresponds to the speaker
terminals that the loudspeakers are connected to.
Make sure unit is not in mute mode.
THERE IS NO SOUND ON ONE CHANNEL
Ensure that balance control is in the correct position.
Check speaker connections.
Check interconnects.
THERE IS A LOUD BUZZ OR HUM
Check turntable or tone arm for ground and connection lead fault.
Ensure no interconnects are loose or defective.
Ensure that your turntable is not too close to the amplifier.
THERE IS WEAK BASS OR DIFFUSED STEREO IMAGING
Ensure that speakers are not wired out of phase.
SPEAKER A/B AND MUTE LIGHT FLASHING
See section on CAP5 protection system.
THE REMOTE HANDSET DOES NOT FUNCTION
Check that the batteries have not expired.
Ensure that nothing is blocking the remote sensor.
For more frequently asked questions (FAQ’s), technical advice and
information on getting the most out of your CXA, please visit the Support
section on Cambridge Audio’s website:
www.cambridgeaudio.com/support
For all servicing, in or out of warranty, please contact your dealer.
5. INTELLIGENT CLIPPING DETECTION
Indication - Volume is reduced automatically.
Description - CAP5 has the ability to detect when the amplifier starts
to clip or overdrive at its output, which can damage loudspeakers, and
degrade the sound. Clipping distortion is caused at high volume levels
when the output signal attempts to go outside the maximum voltage that
the amplifier can provide, causing the tops of the signal to flatten off.
When CAP5 detects clipping the volume will be automatically reduced
down until CAP5 detects an undistorted output.
Note: The clipping detection is disabled by default. The clipping detection
can be enabled in the Setup menu (see 'Setup menu' section).