Service manual

CIRCUIT DESCRIPTION
5-3
April 2001
Part No. 001-9800-203
Figure 5-1 Power Distribution and Switching
Figure 5-2 Power On-Off Control Circuit
+
Chassis
Ground
Vehicle
Battery
15A
Fuse
Power
Cable
Power Amplifier
Board
Transceiver
Power
Connector
CR600
Transient
Suppressor
Unsw Bat
Unsw Bat
Sw Bat
Unsw Bat
J600
J201
1
2
11
J501
J302
F500
4A
Q510
Switch
Front Panel
On-Off Sw
U501
U105
8V
Regulator
5V
Regulator
8V
5.5V
Regulator
8V Tx
Switch
U502
Q504
5.5V
8V Tx
From Shift
Reg U801
From Latch
U112 A/L Bd
Sw Bat
2
5
15
Sw Bat
8V
Vcc
12
J100
J3
Sw Bat
Sw Bat
Sw Bat
J2 J1
2
5
J1
Microphone
Jack
Display Board
Interface
Board
Audio/Logic
Board
RF Board
R533
F100
2A
R2
High Tier
On-Off Sw
On-Off
Latch
(A/L Bd)
Low Tier
4
10
11
High
Tier Only
Front Panel
On-Off Sw
20 18
J3 J302
J100
J201
Q107 Q108
Power Switch
Sense
Ignition On
Sense
To uC,
Pin 60
To uC,
Pin 62
Q110
Power Hold
From Shift Reg
U111, Q7
Unsw Bat
Unsw Bat
R170
From Ignition
Switch
This Resistor Installed If
Ignition Sense Not Connected
Q510
Supply
Switching
Circuit
Interface Board
(High Tier Only)
Audio/Logic Board RF Board
Q109
Sw Bat
Note: Arrows Indicate Signal Flow.
U113A-D
Power On-Off Latch
Low Tier Only
51
grounded which turns that transistor on. C125 then
charges through R185 and applies a high pulse to pins
2 and 4 of NAND gate U113. Then when the switch is
released, Q113 turns off and C125 discharges through
R183-R185.
The latch is formed by NAND gates U113A-D.
The outputs of gates U113C and U113D are always the
opposite state and are fed back to an input of U113A
and U113B (pins 1 and 5). Therefore, pins 1 and 5 are
always the opposite state. When the power switch is
pressed, the output of the gate with a logic high
applied goes low (the other gate does not change
states). This toggles the outputs of U113C and U113D.
When power is turned on, the output on pin 8 goes
high and Q309 is turned on by the current flowing
through R189. Q114 then turns on and grounds the
emitter of Q109. When power is turned off, the oppo-
site occurs.
POWER DISTRIBUTION (ALL MODELS)