Alinco DJ-100, Service Manual

Page: 7 / 36

DJ-100
7
U207
EEPROM
U206
MPU
BATT1
R243
C215
U206
P03
MPU
R244
53
MPU
P14, P15, P16, P17
U206
LCD
U2
LCD
SEG1~SEG40
COM1~COM16
driver
P85, P86
Q1,Q2
SW
LED
P81, P82
D8-D12
D6
SW
DS1
D5
D203
RX LED
D204
TX LED
P2
2
P2
3
Q504
VOL
BATT1
ON/OFF
3.3M
3.3V REG
U101
5C
U500
5V REG
P24
BATT
5M
5V REG
U210
RF power amp (Q502)
Q503
5R
5T
P20
P25
CIRCUIT DESCRIPTION
6-1.
Memory Circuit
Memory circuit consists of the MPU (U206 and an
EEPROM (U207). An EEPROM has a capacity of 128k bits
that contains the transceiver control program for the MPU
and data such as transceiver channels and operating
features. (See Fig. 10)
Fig.10
6-2. Low battery warning
The battery voltage is monitored by the microprocessor
(U206). When the battery voltage falls below the voltage
set by the Low Battery Warning adjustment, the red LED
flashes to notify the operator that it is time to replace the
battery. If the battery voltage falls even more (approx.
6.0V), a beep sounds and transmission is stopped.
Low battery warning Battery condition
The red LED flashes
during transmission The battery voltage is low but
the transceiver is still usable.
The red LED flashes
and a continuous beep
sounds
while PTT
pressed.
The battery voltage is low and
the transceiver is not usable to
make calls.
Fig.11
7. Display Circuit
The MPU (U206) controls the display LCD and LEDs.
When power is on, the LCD driver will use the P81, P82
lines to control the LCD illumination (D5) and key backlight
LEDs (D208~D212 ).
The LCD driver (U2) and MPU (U206) communicate
through the P14, P15, P16, P17, P85, P86 lines.
When the reception is busy, P22 line becomes high
impedance, and the green LED (D203) lights, in transmit
mode, the P23 line becomes high impedance, and the red
Fig.12
8. Power Supply
There are four 5V power supplies for the microprocessor:
5M,5C,5R, and 5T. 5M for microprocessor is always output
while the power is on. 5M is always output, but turns off
when the power is turned off to prevent malfunction of the
microprocessor.
5C is a common 5V and is output when SAVE is not set to
OFF.
5R is 5V for reception and output during reception.
5T is 5V for transmission and output during transmission.
BB is supplied via a ferrite chip from the battery
terminal connected to the TX-RX unit. After passing
through the power switch, power supply (BATT1) is applied
to the three AVRs. U210 supplies 5V (5M) to the control
circuit, and U101 supplies 3.3V (3.3M) to Audio processor
circuits, and U500 supplies 5V (5C) to common circuits.
U500 supplies to the TX circuit, the RX circuit and common
circuits of needless save mode. During transmission, P25
becomes Low and Q503 is turned ON to supply 5V (5T) to
the TX circuit. During reception, P24 becomes Low and
Q504 is turned ON to supply 5V (5R) to the RX Circuit.
Fig.13
LED (D204) lights. (See Fig. 12)