Icom IC-FR3000 manual Other Circuits, Power Supply Circuits

3-4 OTHER CIRCUITS

3-4-1 TELEPHONE IF CIRCUIT (LOGIC UNIT)

The signals from the telephone line (FRONT, J13) are applied to the ringer detect circuit (IC48, D1, D5, R131, R143, R145, C100, C103, C375). The detected signals are applied to the CPU (IC33, pin 73) via “RING” line. The “HOOKC” signal from the CPU (IC33, pin 72) and the “DP” signal from IC47 are applied to the hook switch (RL1, RL2) to off-hook.

Received AF signals from the RX unit pass through the high- pass filter (IC9, pins 5, 7, 12, 14), de-emphasis (IC9, pins 1,

2)and low-pass filter circuits (IC10, pins 1, 3, 5, 7, 8, 9). The filtered AF signals are amplified at IC7 (pins 12, 14) and are then applied to the network IC (IC46, pin 16) via T6. The out- put signals from IC46 are applied to the J13 (FRONT unit) via L1, L2.

AF signals from J13 (FRONT unit) are applied to the network IC (IC46, pins 8, 9). The output signals from IC46 (pins 8, 9) are applied to the AF amplifier IC (IC1, pins 1, 2) via T8. Amplified signals pass through the MIC mute switch (IC1, pins 3, 4), the MIC mixer amplifier (IC2, pins 13, 14), the pre- emphasis circuit (IC2, pins 8, 9), the high-pass filter circuit (IC2, pins 1, 2, 6, 7), limiter amplifier circuit (IC3, pins 1, 2), S-mixer circuit (IC3, pins 6, 7), and splatter filter circuit (IC4, pins 1, 3, 5, 7, 8, 10). The filtered signals are applied to the TX unit.

After off-hook condition, DTMF signal from telephone line is applied to the decoder IC (IC31) to decode the DTMF signal. The DTMF signal is applied to the CPU (IC33) via serial sig- nal line.

The clear down signal is detected at IC45 and is then applied to the CPU (IC33). The “HOOKC” signal from the CPU (IC33, pin 72) and the “DP” signal from IC47 are applied to the hook switch (RL1, RL2) to on-hook.

3-4-2 EEPROM CIRCUIT (LOGIC UNIT)

The detector IC (IC34) detects power supply ON-OFF volt- age. The signal from IC34 is applied to IC33 (CPU). IC35, IC36 are reset signal circuit which stabilizes memory data for the EEPROM (IC37).

EEPROM (IC37) memories clone data and adjust setting condition data.

3-4-3 TEMPERATURE DETECT CIRCUIT (LOGIC UNIT)

The temperature detect circuit protects the power amplifier and power supply circuit from high temperature and stabi- lizes the output power.

Inside temperature of the PA unit is detected at D15 (PA unit) and is then applied to the amplifier IC (PA unit; IC3). The amplified signal is applied to the CPU (IC33) to analyze the temperature via IC32.

Inside temperature of the REG unit is detected at D6 (REG unit) and is then applied to the amplifier (REG unit; IC9). The amplified signal applied to the CPU (IC33) to analyze the temperature via IC32.

IC32 selects “PATEMP” or “REGTEMP” signals from the PA or REG unit.

3-5 POWER SUPPLY CIRCUITS

3-5-1 LOGIC AND REG UNITS VOLTAGE LINES

Line	Description
PS 15V	The voltage from the DC power unit (CHASSIS;
	EP1).
VCC1	The same voltage as the PS 15V line which is
	controlled by the power switch.
	Common 9 V for converted from the VCC1 line
M9V	by the M9V regulator circuit (REG unit; IC1, Q8,
	Q9). The voltage is applied to the TX and RX
	units.
L9V	Common 9 V converted from the VCC1 line by
	the L9V regulator circuit (REG unit; IC2).
A5V	Common 5 V converted from the L9V line by the
	A5V regulator circuit (REG unit; IC3).
	Common 5 V converted from the L9V line by the
L5V	L5V regulator circuit (LOGIC unit; IC38, Q48,
	D43).
	Common 5 V converted from the L9V line by the
C5V	C5V regulator circuit (LOGIC unit; IC38, Q45,
	D13).
TEL5V	Common 5 V converted from the M9V line by the
	TEL5V regulator circuit (LOGIC unit; IC11).

3-5-2 RX UNIT VOLTAGE LINES

Line	Description
+5V	Common 5 V converted from the M9V line by the
	+5V regulator circuit (RX unit; IC3).
+6V	Common 6 V converted from the M9V line by the
	+6V regulator circuit (RX unit; IC7).
R5V	Receive 5 V converted from the R9V line by the
	R5V regulator circuit (RX unit; IC6).
	Receive 9 V controlled by the R9V regulator cir-
R9V	cuit (RX unit; Q15) using “R9C” signal from IC39
	(LOGIC unit).
V9V	Common 9 V converted from the M9V line by the
	V9V regulator circuit (RX unit; Q24).

3-5-3 TX UNIT VOLTAGE LINES

Line	Description
T5V	Transmit 5 V converted from the M9V line by the
	T5V regulator circuit (TX unit; IC1).
T6V	Transmit 6 V converted from the M9V line by the
	T6V regulator circuit (TX unit; IC4).
V9V	Common 9 V converted from the M9V line by the
	V9V regulator circuit (TX unit; Q6).

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