Polaroid IC-V8000 service manual 2 D/A Convertor IC Main Unit IC5, 3 I/O Expander IC Main Unit IC2

4-5-2 D/A CONVERTOR IC (MAIN UNIT: IC5)

Pin	Port	Description
number	name
2	MOD	Outputs transmit devetion control sig-
		nal.
3	SQLATT	Outputs attenuator control signal.
		• Outputs tunable bandpass filter con-
10	T1	trol signal while receiving.
		• Outputs TX power control signal
		while transmitting.
11, 23	T2, T3	Output tunable bandpass filter control
		signals.
14	SQLIN	Outputs squelch control signal.
15	DTC	Outputs DTCS’s gradient control sig-
		nal.
22	FC	Outputs reference frequency control
		signal to X1.

4-5-3 I/O EXPANDER IC (MAIN UNIT: IC2)

Pin	Port			Description
number	name
		Outputs cooling fan control signal.
		The fan speed is depended as shown
		below.
4	FANC1
7	FANC	Fan speed		FANC	FANC1	FANC2
12	FANC2	Hi		H	H	H
		Middle		H	L	H
		Low		H	H	L
6	AFMUTE	Outputs AF mute circuit control signal.
		High : While AF mute is ON.
		Outputs TX and RX VCO’s regulator
11	SHIFT	control signals.
		High	: While receiving.
		Low	: While transmitting.
13	RXC	Outputs R5 regulator control signal.
		Low	: While receiving.
14	TXC	Outputs TX power control signal.
		High : While transmitting.

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