Service Notes And Precautions - Sanyo FXD-770GD Service Manual

SERVICE NOTES AND PRECAUTIONS

SERVICE NOTES
1. Make sure that the power lead is connected properly to
power source, otherwise damage to radio may result. If a
battery eliminator is used as a power source in place of a
battery, it must be filtered and regulated. (The power sup-
ply capacity should be more than 5 amps.)
2. Integrated circuits (ICs) are used in this unit. Because the
ICs are direc-coupled devices, as to all electronic equip-
ment, reading within 10% of the indicated values are ac-
ceptable. Allowance must also be made for variations in
supply voltage. It is expected that any breakdown within
the IC results in drastic changes of the operating voltages
at the terminals.
3. When replacing a power output IC, remember to use the
IC specified in the parts list; Coat the IC-fin with silicon
grease.
WARNING
ln using meters, signal generator and any tool in servicing
Ics, extreme care is needed. DO NOT SHORT THE IC TER-
MINALS TO THE PATTERN ON THE PC BOARD OR TO
EACH OTHER. THE IC WILL BE INSTANTANEOUSLY DE-
STROYED.
ALIGNMENT PROCEDURE
Alignment is performed at factory with laboratory equipment.
Therefore, before alignment is attempted, the unit should be
thoroughly checked for circuit troubles.
NOTES:
1. Check for specified source voltage-DC, 14.4volts.
2. Connect an AC voltmeter (AC VM) across speaker or
dummy load (4 ohms. 20W, wirewound resistor)...see Fig.
1-3. (ELECTRICAL ADJUSTMENTS)
3. Signal input must be kept as low as possible to avoid over-
load and clipping (use highest sensitivity of output indica-
tor).
4. Repeat adjustment to ensure good results.
5. Non-metallic alignment tools must be used (especially at
FM alignment).
6. For alignment location details, refer to CIRCUIT BOARD
PARTS LOCATION.
INSTALLATION PROCEDURE
1. To prevent a short circuit, remove the key from the igni-
tion and disconnect the
2. Make the proper input and output wire connections for
each unit.
3. Connect the wiring harness wires in the following order:
ground, speakers, battery, ignition.
4. Connect the wiring harness connector to the unit.
5. Install the unit in your car.
6. Reconnect the
7. Disinstall by reversing the installation procedure.
CAUTI0N
• The rear-panel which also heatsink is very hot. Don't burn!!
• If your car's ignition does not have an ACC position, con-
nect the ignition wires to a power source that can be turned
on and off with the ignition key. If you connect the ignition
wire to a power source with a constant voltage supply, as
with battery wires, the battery may die.
• If the console has a lid, make sure to install the unit so
that the cover will not hit the lid when closing and open-
ing.
• If the fuse blows, first make sure the wires aren't touching
to cause a short circuit, then replace the old fuse with one
with the same rating.
• Do not let unconnected wires or terminals touch metal on
the car or anything else conducting electricity. To prevent
a short circuit, do not remove the caps on the ends of the
unconnected wires or the terminals.
• Connect the speaker wires correctly to the terminals to
which they correspond. The unit may be damaged or fail
to work if you share the
metal part in the car.
• After the unit is installed, check whether the brake lamps,
blinkers, wipers, etc. on the car are working properly.
• Insulate unconnected wires with vinyl tape or other simi-
lar material .
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battery.
battery.
wires or ground them to any