Other Circuits; Power Supply Circuits; Port Allocations - Icom IC-F24 Service Manual

4-4 OTHER CIRCUITS

LED CONTROL CIRCUITS
The LED control circuit is composed of the CPU (IC13),
LED driver (Q32) and LED (DS1).
The CPU outputs "RLED" and "TLED" signals from the pins
42 and 43. The signals are applied to the LED driver (Q32,
pins 2 and 5). The driver outputs LED control signals to the
LEDs (DS1).
CONDITION
RECEIVING (2/5-TONE CODE)
LOW BATTERY
(Nearly exhausted)
LOW BATTERY
(Almost exhausted)
CLONING
RECEIVING/SQUELCH OPEN
TRANSMITTING
4-5 POWER SUPPLY CIRCUIT
VOLTAGE LINE
LINE
VCC The voltage from the connected battery pack.
Common 5 V converted from the VCC line at
the +5 regulator circuit (IC9). The output voltage
+5V
is supplied to the D/A converter (IC8), analog
SW (IC10), etc.
Common 5 V converted from the VCC line at
the S5 regulator circuit (Q23–Q25). The output
S5V
voltage is supplied to the ripple filter (Q17), PLL
IC (IC4), etc.
Receive 5 V converted from the S5V line at the
R5 regulator circuit (Q22). The output voltage
R5V is supplied to the tripler (Q19), FM IF IC (IC1),
IF amplifier (Q4), VCO switch (Q15, Q16), 1st
mixer (Q3), etc.
Transmit 5 V converted from the S5V line at the
T5V T5 regulator circuit (Q21). The output voltage is
supplied to the YGR (Q9), pre-drive (Q5), APC
amplifier (IC2), etc.
COLOR
ORANGE (Lighting)
RED (Blinks Slowly)
RED (Blinks Fast)
ORANGE (Blinking)
GREEN (Lighting)
RED (Lighting)
DESCRIPTION
4-6 PORT ALLOCATION
4-6-1 D/A CONVERTER IC (IC8)
Pin Port
number name
11 BAL
14 LVA
15 REF
22 T1
23 T2
4 - 5
Description
Outputs the modulation balance level
control signal. The signal is applied
to the reference frequency crystal
oscillator (X2, pin 1).
Outputs the PLL lock voltage control
signal. The output signal is applied to
the RX VCO (Q14, D16, D22) and TX
VCO (Q13, D17, D21).
Outputs the reference oscillator
correcting voltage. The voltage is applied
to the reference frequency crystal
oscillator (X2, pin 1).
Outputs the bandpass filter tuning
signal. The output signal is applied to
the bandpass filters (D3, D4, D7, D8).
• Outputs the bandpass filter tuning
signal during receive. The output
signal is applied to the bandpass
filters (D9, D10).
• Outputs the TX power control signal
during transmit. The output signal is
applied to the APC amplifier (IC2,
pin 1).