Kenwood R-V251 User manual

AV SURROUND RECEIVER
R-V251
SERVICE MANUAL
© 1999-8/B51-5562-00 (K/K) 1792
70%
Caution : No connection of ground line if disassemble the unit.
Please connect the ground line on rear panel, PCBs, Chassis and some
others.
* Refer to parts list on page 25
ON/STANDBY
PHONES
INPUT TAPE 2
(MONITOR)
TA/NEWS
/INFO. DISP. AUTO A.MEMO BANDPTY
CLOCK MODE
TIMER
SET
TUNING
MODE MULTI CONTROL
LEVEL
VOLUME CONTROL
DOWN UP
AV SURROUND RECEIVER R-V251
R D S
EON
SYSTEM
CONTROL
FRONT
SURROUND
CENTER
SUB WOOFER
SUB WOOFER
PRE OUT
REAR FRONTCENTER
SPEAKERS
( 6-16Ω )
UNSWITCHED TOTAL
150W MAX.
AC 230V 50Hz
ANTENNA
AM
FM 75Ω
GND
TAPE 2
(MONITOR) TAPE1 / MD
CD AUX
IN
REC VCR PLAY
REC PLAY REC PLAY
R
L
L
AUDIO
VIDEO
VCR
REC OUT
MONITOR
OUT DVD
VCR
PLAY IN
L
R
RLC
1 3
10
15 17 19
12
11
2IN 4
9 5 7
5 7
DVD 6CH./2CH.INPUT
R
16 18 20
22
43
3133393735
34 3236 38 40
Panel dressing
(A21-3777-03) Window (B10-2367-02) Panel * (A60-)
Knob
(k29-6727-04)
Button(R) *
(K29-)
Button(L)
(K29-6816-02)
Phono jack(4P)
(E63-0186-08) Phono jack(6P)x2
(E63-0187-08)
Lock terminal board
(E70-0120-08)
Phono jack
(E63-1137-08) Phono jack(6P) (E63-1136-08) AC outlet *
(E03-)
Lock terminal board
(E70-0119-08) Power cord bushing (J42-0346-08)
Metallic cabinet
(A01-3750-08)
Lock terminal board
(E21-0034-08) Phono jack(4P) (E63-1152-08) Phone jack (E11-0188-05)
AC power cord *
(E30-)

R-V251
2
CONTENTS / ACCESSORIES / CAUTIONS
Contents
CONTENTS / ACCESSORIES / CAUTIONS............. 2
BLOCK DIAGRAM......................................................3
CIRCUIT DESCRIPTION............................................4
ADJUSTMENT............................................................8
PC BOARD ................................................................ 9
SCHEMATIC DIAGRAM.......................................... 13
EXPLODED VIEW ....................................................24
PARTS LIST..............................................................25
SPECIFICATIONS....................................................31
FM indoor antenna (1)
(T90-0830-08) AM loop antenna (1) (T90-0804-08)
Remote control unit (1)
(A70-1306-05): RC-S0506...TE
(A70-1305-05): RC-S0505...X Battery cover (A09-0378-08)
Loop antenna stand (1) Batteries(R6/AA)
REMOTE CONTROL UNIT
RC-S0506
A B
+10
54321
09876
6
7
8
8
%
fi
¢
¢
4
4
¡
1
¡3
3
7
7
°
2
2
1
ALL INFO.TEXT DISP.
TITLE
SEARCH
MEMO
TUNER
BAND
e
STILL STEP
E
A.MONI.
AUTO
MEMORY
RDS
DISPLAY
PTY
SEARCH
DISPLAY
SLEEP
NEXTPREV.
POWER
TIME
CLEAR
P.MODE
CHECK
STEREO
MUTE
SOURCE
DIRECTDSP
LEVEL VOLUME
PRO LOGIC 3 STEREO
MULTI
CONTROL
TEST
TONE
MODE
INPUT TAPE 2
(MONITOR)
FREEZE
PAL/NTSC
RETURN
TAPE
MD/LO
SELECT
P.B.C.
¶REC/ARMO.T.E.
LD
AUTO DIGITAL
CD/VIDEO CD/LD REPEAT
FRAME/
TIME
PTY
TA/NEWS/INFO.
DISC SKIPEDIT MODE
ALL TEXT
SEARCH
P.CALL
fi %
How to reset the microcomputer
The microcomputer may malfunction (impossibility of operation,
erroneous display, etc.) when the power cord is unplugged and
plugged in again while the unit is in ON mode with the key
pressed or due to other external causes. In this case, execute the
procedure on the right to reset the microcomputer and return the
unit to the normal condition.
Unplug the power cord from the wall outlet.
While holding the (ON/STANDBY) key depressed,
plug the power cord into the wall outlet again.
Resetting the microcomputer clears the memory you entered and
returns it to the initial condition when the unit left the factory.
Accessories
Cautions

FL DISPLAY
TUNER UNIT
K01
POWER AMP
K02
K03
K02
BD101
7815
+VH(AMP)
-30V
AVR
KEY MATRIX
STK411-210E
IC103
STK410-010E
IC104
Q119-124Q113-118
NJM2068D
IC113
HEADPHONES
L
R
L
R
SPEAKER
C
SL
SR
SW-PRE OUT
M62446FP
IC107
ELECTRIC TONE
/VOLUME
BD102
IC101
7915
IC102
Q101
-VH(AMP)
+VL(AMP)
-VL(AMP)
F1
FILAMENTAC
FL DISPLAY
+5V(u-COM)
+10V(PRO LOGIC)
+5V(VIDEO SEL)
+7V(E.VOL)
+15V
-15V
-5V(VIDEO SEL)
-7V(E.VOL) F2
IC106(2/2)
TC9163AN
IC111
NJM2068D
IC112
NJM2068D
IC105
CDX271AQ
IC110
NJM2068D
IC702(2/2)
NJM2068D
IC603
-6ab ATT
IC702(1/2)
LC7821
IC601
LC7821
IC106(1/2)
DOLBY
PROLOGIC
IC108
NJM2279
SELECTOR
VIDEO
TUNER
CD
AUX
MD PLAY
PLAY
TAPE/MONITOR
VIDEO PLAY
TAPE/MONITOR
REC
MD REC
VIDEO REC
VIDEO PLAY
VIDEO REC
DVD/GCH INPUT
MONITOR OUT
L
R
C
SL
SR
SW
DVD
GCH INPUT
IC701
u-COM
FLT701
+
+
+
+
+
+
+
MUTE
L
R
C
SL
SR
SW
C
R
L
SW
SR
SL
-10ab ATT
-B LOW TAP
-B HI TAP
+B LOW TAP
+B HI TAP
L
R
C
S
L
RR
GRID
REMOCON IN ROTARY ENCODER RELAY VIDEO1,VIDEO2,VMUTE E.VOL (DATA,CLK,STB) 10ab ATT MUTE TUNER RESET P/L (DATA,CLK,STB) SYNCHRD RDS PROTECTION
SEGMENT
KEY SCAN
KEY RETURN
R-V251
R-V251
3
BLOCK DIAGRAM

R-V251
4
CIRCUIT DESCRIPTION
Active
Pin. No. Pin Name I/O Description HL
1,2 G1,G2 O FL grid control.
3 PULL UP - Connected to VCC(+5.0V).
4 POWER DOWN I AC selector.
5 VOL. UP I Volume encoder A(CW) signal.
6 RDS CLK I RDS IC(IC703) clock input control.
7 VOL. DOWN I Volume encoder B(CCW) signal.
8 RMC I Remote control signal input.
9 RDS DATA I RDS IC(IC703) data input control.
10,11 NC - Unused.
12 PROTECTION I Detection input port of protection. ON
13 STEREO I Detection input port of stereo signal for TUNER. STEREO
14 PLL CE O PLL IC(IC402) CE signal output.
15 RCVR CLK O SEL. IC(IC601,602,106) clock signal output.
16 RCVR DATA O SEL. IC(IC601,602,106) data signal output.
17~19 KEY3~1 I Key return 3~1.
20 S. DATA I/O Serial communication data.
21 S. BUSY I/O Serial communication busy.
22 E.VOL CK O E.volume IC(IC107) clock control. ACTIVE
23 E.VOL DT O E.volume IC(IC107) data control.
24 E.VOL ST O E.volume IC(IC107) strobe control. ACTIVE
25 PLL DO I PLL IC(IC402) DO signal.
26 RCV CE I Receiver chip enable signal. ENABLE
27 DSP CE O DSP IC(IC105) XLAT.
28 AVREF - Analog power supply(+5.0V).
29 H/P DETECT I Detection input port of headphones jack.
30 SD I Detection input port of SD signal for TUNER. TUNED
31 S. LEVEL I A/D input port of signal level.
32 DSP READY O DSP IC(IC105) ready.
33 DSP DATA O DSP IC(IC105) data.
34 DSP CLK O DSP IC(IC105) clock.
35 OPT I Discrimination port of model. E,T X
36 CH.SPACE - Unused.
37 AVSS - Analog ground.
38 RESET I u-COM reset.
39 EXTAL I Main clock(10MHz).
40 XTAL - Main clock(10MHz).
41 VSS - u-COM ground.
42 TX - Sub clock(32.768kHz).
43 TEX I Sub clock(32.768kHz).
44 VDD - Power supply(+5.0V).
45 VFDP - FL power supply(-33V).
46 T. MUTE O Muting control of TUNER. ON
47 MAIN MUTE O Muting control of main output. ON
48 H/P MUTE O Muting control of headphones. ON
49 VCR MUTE O VIDEO IC(IC108) control. ON
50 DSP RESET O DSP IC(IC105) reset.
51 RCV. CE I Receiver chip enable signal.
52 - - Unused.
53 F. RLY O Front speaker relay control. ON
54 S. RLY O Surround speaker relay control. ON
55 C. RLY O Center speaker relay control. ON
1. Microprocessor : (FRONT PCB,IC701)
1-1. Pin description

Pin No. Name I/O Description
1~3 T.P O Test monitor. Normally outputs Low.(Unused.)
4 VSSO - Digital GND.
5~8 T.P O Test monitor. Normally outputs Low.(Unused.)
9 TSTO I Digital GND.
10 VDDO - Digital power supply.
11 VSS1 - Digital GND.
12~15 TST1~4 I Digital GND.
16 XRST I System reset input. Reset when Low.
17 BFOT O Unused.
18 CSL1 I Digital power supply.
19 CSL2 I Digital GND.
20 VSS2 - Digital GND.
21 AVS3 - L-ch DA converter GND.
22 AVD3 - L-ch DA converter power supply.
23 LOUT O L-ch DA converter output.
24 AVD1 - L-ch AD converter power supply.
25 AVS1 - L-ch AD converter GND.
26 L01 O L-ch AD converter LPF operational amplifier inverted output.
27 LIN I L-ch AD converter analog input.
28 AVD5 - C-ch DA converter power supply.
29 AVS5 - C-ch DA converter GND.
30 XCOUT O C-ch DA converter output.
31 AVDX - Analog power supply for master clock.
32 XTLO O Crystal oscillator circuit output.
33 XTL1 I Crystal oscillator circuit input.
34 AVSX - Analog GND for master clock.
35 XSOUT O S-ch DA converter output.
36 AVS6 - S-ch DA converter GND.
37 AVD6 - S-ch DA converter power supply.
38 RIN I R-ch AD converter analog input.
39 LO2 O R-ch AD converter LPF operational amplifier inverted output.
40 AVS2 - R-ch AD converter GND.
R-V251
5
CIRCUIT DESCRIPTION
Active
Pin. No. Pin Name I/O Description HL
56 POWER RLY O Power relay control. ON
57 10dB. ATT O Volume 10dB attenuator control. ON
58 ST. LED O STANDBY LED control(RED). ON
59 ST. LED O STANDBY LED control(GREEN). ON
60~69 - - Unused.
70~77 9S~16S O FL segment(9~16) and key scan(1~8) control.
78~85 1S~8S O FL segment(1~8) control.
86~88 - - Unused.
89 VDD - u-COM power supply(+5.0V).
90,91 - - Unused.
92~100 G11~G03 O FL grid control.
2. Key matrix
3. Pin description of dolby prologic IC(MAIN PCB IC105)
KS1(77pin) KS2(76pin) KS3(75pin) KS4(74pin) KS5(73pin) KS6(72pin) KS7(71pin) KS8(70pin)
K1(19pin) MODE TUNING - - - - PTY AUTO
TIMER TIMER TIMER
K2(18pin) MULTI TUNING CLOCK - MODE SET TA MEMO
K3(17pin) MULTI - INPUT
ON/STBY INPUT TAPE2 DISP BAND