Volvo Delco Manual de usuario
Service Bulletin
Volvo Trucks North America, Inc.
Greensboro, NC USA
Date Group No. Page
4.2004 392 08 1(47)
Trucks
This Service Bulletin replaces Service Manual 39, “Delco
Audio System Troubleshooting, VN” (12.1998), publication
number PV776–TSP109859. Audio System Design and Function
Delco/Delphi
VN, VHD
Audio System
Delco/Delphi
This service information covers the Delco/Delphi System Design and Function. For
further information refer to Group 3.
Contents:
•“VolvoVNSoundSystem”page2
•“RadioSignals”page3
•“Noise”page9
•“TroubleshootingConsideration”page10
•“StereoReceiver”page11
•“WeatherbandFamily”page11
•“HighPerformanceFamily”page14
•“CDChanger—HighPerformanceFamily”page27
•“CDChangerMagazine”page29
•“Amplifier”page38
•“Speakers”page39
•“Antenna”page41
•“Schematics”page45
Note: Information is subject to change without notice.
Illustrations are used for reference only and may differ slightly from the actual
vehicle being serviced. However, key components addressed in this information are
represented as accurately as possible.
PV776-20002689 USA14750
Volvo Trucks North America, Inc. Date Group No. Page
Service Bulletin 4.2004 392 08 2(47)
Volvo VN Sound System
The audio receiver systems in the Volvo VN series trucks
are selected and tuned for optimized performance. All
VN models are available with a variety of Delco/Delphi
Electronics components.
Three receiver families are available:
•The Weatherband family is available with or without
a cassette player or early production VNs through
approximately June 1999.
•The High Performance family is available with a
cassette or CD player on early production VNs through
approximately June 1999.
•The Extreme Audio family, known as XTA, is available
on later production VNs beginning approximately June
1999. It is standard on the VHD vehicles. The XTA
series is available in a “Basic” system with or without
a cassette player, and an “Uplevel” system with a
cassette or CD player.
All VN/VHD models are also available with either basic
or premium speaker packages. The VN 770 premium
speaker system includes an 8 channel amplifier and a
subwoofer. The VN 660 and VN 770 models are available
with remote CD changers.
Consult the “Owner’s Manual” that is supplied with the
vehicle for complete operation instructions.
Repair/Replacement
As an alternative to expensive replacement, Delco/Delphi
Electronics Devices may be repaired at approved service
centers. Call D&B Auto Radio at 1-800-323-4813 for
repair information.
Unauthorized Repair
The warranty may not apply if the product is worked on
by an unauthorized person.
Volvo Trucks North America, Inc. Date Group No. Page
Service Bulletin 4.2004 392 08 3(47)
Radio Signals
The radio signal is sent from a broadcast station and this
signal is then received by an antenna. The strength of the
signal depends on the following:
•The power output (wattage) of the broadcasting station.
•The location of the receiver relative to the broadcast
tower.
•Obstacles between the tower and the receiver.
•Atmospheric conditions.
•What band (AM or FM) the station is broadcasting.
•Type of antenna and the grounding bases.
In North America, commercial radio signals are legislated
into two bands:
•AM 530-1710 kHz (in 10 kHz steps)
•FM 87.9-107.9 MHz (in 200 kHz steps)
Each frequency range uses a different modulation
method. Since a radio wave is really just electromagnetic
energy, it must be controlled in a certain way to carry
information. The process of adding the information to the
radio signals is called modulation.
There are two modulation techniques used in radio
broadcasts:
•AM = Amplitude Modulation
•FM = Frequency Modulation
The characteristics of the signal depend on both
the frequency and the modulation. It is important to
understand these characteristics to properly verify a
complaint.
Volvo Trucks North America, Inc. Date Group No. Page
Service Bulletin 4.2004 392 08 4(47)
AM Band
W3003003
AM radio signals. (100 km = 62 miles)
Radio signals in the AM band have lower frequency
and longer wavelengths than the FM band. Some
characteristics of the AM band include:
•The frequency used is relatively low; therefore, these
waves can bend around obstacles and skip along the
ground.
•The waves are reflected by the ionosphere layer in the
atmosphere.
•Long range reception is sometimes available.
•AM is subject to electrical interferences.
•AM can be blocked by steel and/or concrete structures.
The AM frequencies have longer range due to the ground
wave. The ground wave follows the curvature of the
earth and is effected by its conductivity. The greater the
conductivity, the less the signal loss; so transmission
over water is better than over land. The ground wave in
this frequency band has a range of 80–320 kilometers
(50–200 miles).
The sky wave will pass through the atmosphere and
reflect off of the ionosphere to the vehicle’s antenna. At
night, the ionosphere is actually higher than during the
day, so it is possible for AM signals from great distances to
be received during nighttime hours. As a result, many AM
stations actually reduce transmitting power in the evening
hours to maintain the same coverage as during the day.
Volvo Trucks North America, Inc. Date Group No. Page
Service Bulletin 4.2004 392 08 5(47)
FM Band
W3003002
FM band signal. (100 km = 62 miles)
Radio signals in the FM band have higher frequency
and shorter wavelengths than the AM band. Some
characteristics of the FM band include:
•FM is able to eliminate atmospheric noise mainly due
to its method of propagation. Atmospheric noises are
generally amplitude related and have little effect on
FM signals.
•Reflect off of obstacles.
•Penetrate the ionosphere.
Radio frequencies over 30 MHz are effectively absorbed
by the earth, eliminating the ground wave. Even when out
of a direct line of sight, the signal may be reflected into
areas that would be in a “shadow” otherwise.
FM signals and light rays respond to atmosphere in a
similar manner. The atmosphere bends them both so they
will follow the curvature of the earth to a certain extent.
This is called refraction and it is similar to a lens which
can bend light waves. A good example of this is when
you see a sunset. The sunlight is visible with the sun well
below the horizon. FM signals characteristically have a
shorter range than AM signals.
Factors which affect the line of sight include:
•Height of the broadcast antenna.
•Height of the receiving antenna.
•Terrain and buildings in the broadcast path.
Volvo Trucks North America, Inc. Date Group No. Page
Service Bulletin 4.2004 392 08 6(47)
Weatherband
NOAA — (National Oceanic and Atmospheric
Administration) is a service of the “Voice of the National
Weather Service.” It provides continuous broadcasts of
the latest weather information directly from the National
Weather Service offices. Taped weather messages are
repeated every four to six minutes and are routinely
revised ever one to three hours, or more frequently if
needed. Most of the stations operate 24 hours a day.
The weather for your area can be found on one of seven
stations. The frequency associated with each channel
is as follows:
•162.550 MHz
•162.400 MHz
•162.475 MHz
•162.425 MHz
•162.450 MHz
•162.500 MHz
•162.525 MHz
Approximately 90 percent of the nation’s population
is within listening range of a NOAA Weather Radio
broadcast.
Volvo Trucks North America, Inc. Date Group No. Page
Service Bulletin 4.2004 392 08 7(47)
Signal Disruption
W3003001
Since the higher frequency signals behave more like
light, the signal may be reflected or there may be areas
of shadow. When a receiver has more than one signal
due to reflection, we call it multipath distortion. When a
receiver is located in a signal shadow, we call it flutter.
Multipath
This condition is caused by reflected signals. The
reflected signal must travel further than the direct signal,
so it takes longer to get to the antenna and it is weaker
when it gets there. The receiver then has two signals
which are slightly out-of-time with each other. The two
signals tend to cancel each other out. This condition is
most common in built-up areas which reflect the signals.
A multipath area is often only a few inches wide. At home
you can locate the antenna to avoid a multipath area, but
in your vehicle you may drivein and out of multipath areas.
Flutter
Flutter occurs when the signal strength is too low to allow
proper reception. Flutter can occur when in a fringe area
of a transmitter. Flutter can occur much closer to the
transmitter if the receiver is located in a signal shadow.
In a strong signal area, reflection will generally fill in
the reception shadows. When there is little to support
reflection, an obstacle may cause a signal shadow.
Operating in the shadow will cause flutter. This may also
be called “picket fencing”.
Volvo Trucks North America, Inc. Date Group No. Page
Service Bulletin 4.2004 392 08 8(47)
Electrical Interference
Electrical interference signal disruptions may come from
electrical fields near high tension power lines, vehicle
electrical devices or other high power radio signals.
Strong FM band signals are usually not affected by
electrical interference.
Atmospheric Interference
A loss of sensitivity (especially from stations more than
25 miles away) may be due to atmospheric conditions. An
increase in sensitivity for a short period may be due to a
complementing atmospheric alignment.
Electrical storms will cause atmospheric interference,
especially in the AM band.
Volvo Trucks North America, Inc. Date Group No. Page
Service Bulletin 4.2004 392 08 9(47)
Noise
Noise is an undesirable interference in the audio system.
Noise can enter the audio system one of two ways,
conducted or radiated.
•Conducted noises will have a physical connection to
the audio system through one of the audio system
circuits.
•Radiated noises have no physical connection to
the audio system, but the electrical or magnetic
fields reaching the audio system or wiring induce an
electrical effect causing noise.
In diagnosing noise complaints, technicians may need
to identify noise sources that are physically connected
(back-way noise) or sources affected only by radiation.
The vehicle contains many “noisy” components which
radiate an electromagnetic signal. As the distance
from the radio transmitter station increases, on-board
components may begin to compete with desired radio
signals. The following pages will help isolate the cause of
radio noise and suggest a fix.
EMI / RFI
EMI (Electromagnetic Interference) is the undesirable
interference of an electrical system via radiated emissions
from another electrical system.
The term “EMI” includes all disturbances in the
electromagnetic spectrum. Within the EMI category
is a smaller group known as RFI (Radio Frequency
Interference). This is the frequency group of EMI that is
the radio frequency band.
RFI characteristics:
•RF (Radio Frequency) waves are radiated when a
high-frequency current and proper geometry exist in
a circuit.
•Waves travel in all directions and pass easily through
non-conductive materials.
•Waves are reflected by conductive materials unless the
geometry is correct for absorption. If so, then the wave
is converted into electrical potential.
The energy radiated relates to the amount of energy in
the circuit and the geometry.
Volvo Trucks North America, Inc. Date Group No. Page
Service Bulletin 4.2004 392 08 10(47)
If conditions are correct, the RF wave is absorbed into the
system and will induce stray currents internally within the
system. RFI has the capability to cause disturbances over
longer distance because of the probability of susceptible
devices being highly sensitive. Therefore, RFI can be
very difficult to combat in some cases so good diagnostic
practices are absolutely required.
Some possible vehicle sources of interference:
•Charging system
•Solenoids
•Motors
•Engine electronics
•2–way radios
•Citizen band (CB) radios
•Cellular phones
•Satellite Communication systems
•After-market electrical devices
Troubleshooting Consideration
When troubleshooting radio reception problems consider
problems associated with radio signals. Do not attempt to
troubleshoot radio problems:
•inside buildings (steel and concrete structures are
worst).
•in an area with reflected signals (see “Multipath” page
7).
•close to areas with known electrical interference such
as near high tension power lines.
•with electrical storms in the area.
To minimize flutter, tune to radio stations with a strong
signal while troubleshooting.
Este manual sirve para los siguientes modelos
1
Tabla de contenidos
Otros manuales de Sistema estéreo para automóvil de Volvo
