manual radio set LAND ROVER DISCOVERY 1995 Service Repair Manual

ELECTRICAL
1
DESCRIPTION AND OPERATION ELECTRICAL EQUIPMENT
DESCRIPTION
The electrical system is Negative ground, and it is
most important to ensure correct polarity of the
electrical connections at all times. Any incorrect
connections made when reconnecting cables may
cause irreparable damage to the semi-conductor
devices used in the generator and regulator. Incorrect
polarity would also seriously damage any
transistorized equipment such as radio and
tachometer etc.
WARNING: During battery removal or
before carrying out any repairs or
maintenance to electrical components
always disconnect the battery negative lead first.
If the positive lead is disconnected with the
negative lead in place, accidental contact of the
wrench to any grounded metal part could cause a
severe spark, possibly resulting in personal
injury. Upon installation of the battery the positive
lead should be connected first.
GENERATOR
The generator is a three phase, field sensed unit. The
rotor and stator windings produce three phase
alternating current, AC, which is rectified to direct
current, DC. The electronic voltage regulator unit
controls the generator output voltage by high
frequency switching of the rotor field circuit. Use only
the correct Vehicle replacement fan belt. Occasionally
check that the engine and generator pulleys are
accurately aligned.
It is essential that good electrical connections are
maintained at all times. Of particular importance are
those in the charging circuit (including those at the
battery) which should be occasionally inspected to
see that they are clean and tight. In this way any
significant increase in circuit resistance can be
prevented.Do not disconnect battery cables while the engine is
running or damage to the semi-conductor devices
may occur. It is also inadvisable to break or make any
connections in the generator charging and control
circuits while the engine is running.
The electronic voltage regulator employs micro-circuit
techniques resulting in improved performance under
difficult service conditions. The whole assembly is
encapsulated in silicone rubber and housed in an
aluminium heat sink, ensuring complete protection
against the adverse effects of temperature, dust, and
moisture etc.
The regulating voltage is set during manufacture to
give the required regulating voltage range of 14.2±
0.2 volts, and no adjustment is necessary. The only
maintenance needed is the occasional check on
terminal connections and wiping with a clean dry
cloth.
The generator system provides for direct connection
of a charge (ignition) indicator warning light, and
eliminates the need for a field switching relay or
warning light control unit. As the warning lamp is
connected in the charging circuit, lamp failure will
cause loss of charge. Lamp should be checked
regularly and spare carried.
When using rapid charge equipment to re-charge the
battery, the battery must be disconnected from the
vehicle.
NOTE: For description and operation of
electrical circuits see separate publication:
Electrical Troubleshooting Manual.

86ELECTRICAL
10
DESCRIPTION AND OPERATION Radio frequency system
The RF system uses frequencies according to market
and both ECU and handset are colour coded:
Territory ECU/Handset............................... Frequency..................
Europe Blue/Blue.................................. 433.92 MHz.........................
NAS Green/Green....................................... 315.00 MHz....................
Japan Green/Green.................................... 315.00 MHz....................
Gulf Green/Green....................................... 315.00 MHz....................
Rest of World Green/Brown........................ 315.00 MHz...................
NOTE: In service NAS, Japan and Gulf will
have the handset changed to brown.
Passive coil
The passive coil excites a receiving coil in the handset
causing it to automatically transmit a remobilisation
signal to the ECU.
Inertia switch and central door locking
Actuation of the inertia switch will cause the doors to
be unlocked. A time-out period (programmable
between 0-5 minutes) will ensue, during which all CDL
and alarm activity is disabled.
NOTE: This feature only applies when the
starter switch is in the on position.
Handset
Under normal circumstances pressing the respective
buttons on the handset once, will unlock or lock the
vehicle. If operating the handset does not achieve the
desired effect
See Repair, Handset.
Functional detail
For full functional details and circuit diagrams
See
Electrical Trouble Shooting Manual..
Vehicle traceability
All Land Rover vehicles are fitted with a multitude of
discreet security features to prevent theft or assist
recovery in the event of a vehicle being stolen. All
vehicles are traceable, since it is impossible to
remove all security identification.