Circuit Description - Kenwood R-V251 Service Manual

R-V251
1. Microprocessor : (FRONT PCB,IC701)
1-1. Pin description
Pin. No. Pin Name
1,2 G1,G2
3 PULL UP
4 POWER DOWN
5 VOL. UP
6 RDS CLK
7 VOL. DOWN
8 RMC
9 RDS DATA
10,11 NC
12 PROTECTION
13 STEREO
14 PLL CE
15 RCVR CLK
16 RCVR DATA
17~19 KEY3~1
20 S. DATA
21 S. BUSY
22 E.VOL CK
23 E.VOL DT
24 E.VOL ST
25 PLL DO
26 RCV CE
27 DSP CE
28 AVREF
29 H/P DETECT
30 SD
31 S. LEVEL
32 DSP READY
33 DSP DATA
34 DSP CLK
35 OPT
36 CH.SPACE
37 AVSS
38 RESET
39 EXTAL
40 XTAL
41 VSS
42 TX
43 TEX
44 VDD
45 VFDP
46 T. MUTE
47 MAIN MUTE
48 H/P MUTE
49 VCR MUTE
50 DSP RESET
51 RCV. CE
52 -
53 F. RLY
54 S. RLY
55 C. RLY
4

CIRCUIT DESCRIPTION

I/O
O FL grid control.
- Connected to VCC(+5.0V).
I AC selector.
I Volume encoder A(CW) signal.
I RDS IC(IC703) clock input control.
I Volume encoder B(CCW) signal.
I Remote control signal input.
I RDS IC(IC703) data input control.
- Unused.
I Detection input port of protection.
I Detection input port of stereo signal for TUNER.
O PLL IC(IC402) CE signal output.
O SEL. IC(IC601,602,106) clock signal output.
O SEL. IC(IC601,602,106) data signal output.
I Key return 3~1.
I/O Serial communication data.
I/O Serial communication busy.
O E.volume IC(IC107) clock control.
O E.volume IC(IC107) data control.
O E.volume IC(IC107) strobe control.
I PLL IC(IC402) DO signal.
I Receiver chip enable signal.
O DSP IC(IC105) XLAT.
- Analog power supply(+5.0V).
I Detection input port of headphones jack.
I Detection input port of SD signal for TUNER.
I A/D input port of signal level.
O DSP IC(IC105) ready.
O DSP IC(IC105) data.
O DSP IC(IC105) clock.
I Discrimination port of model.
- Unused.
- Analog ground.
I u-COM reset.
I Main clock(10MHz).
- Main clock(10MHz).
- u-COM ground.
- Sub clock(32.768kHz).
I Sub clock(32.768kHz).
- Power supply(+5.0V).
- FL power supply(-33V).
O Muting control of TUNER.
O Muting control of main output.
O Muting control of headphones.
O VIDEO IC(IC108) control.
O DSP IC(IC105) reset.
I Receiver chip enable signal.
- Unused.
O Front speaker relay control.
O Surround speaker relay control.
O Center speaker relay control.
Description
Active
H L
ON
STEREO
ACTIVE
ACTIVE
ENABLE
TUNED
E,T X
ON
ON
ON
ON
ON
ON
ON