Sherwood RD-7502 User manual

RD-7502
AUDIO/VIDEO RECEIVER
SAFETY PRECAUTIONS ................................... 1
SPECIFICATION ................................................. 2
VIDEO SECTION ................................................ 5
TUNER SECTION ............................................... 9
BLOCK DIAGRAMS ......................................... 11
WIRING DIAGRAM .......................................... 13
CIRCUIT DESCRIPTION ................................... 14
TUNER ALIGNMENT ....................................... 17
TROUBLESHOOTING ...................................... 18
MECHANICAL PARTS LIST ............................. 21
EXPLODED VIEW ............................................. 22
ELECTRICAL PARTS LIST ................................ 23
IC’S FUNCTIONAL BLOCK DIAGRAMS.......... 30
PRINTED CIRCUIT BOARDS ............................ 39
SCHEMATIC DIAGRAMS................................. 46
CONTENTS
R

1
SAFETY PRECAUTIONS
WARNING
Before servicing this unit, familiarize yourself with the following precautions:
1. Many electrical and mechanical parts in this
chassis have special safety characteristics that
often pass unnoticed and the protection
afforded by them cannot necessarily be
obtained by using replacement components
rated for higher voltage, wattage, etc.
Replacement parts that have these special
safety characteristics are identified in this
manual and its supplements: electrical
components having such features are identified
by in the schematic diagram and the parts
list.
Before replacing any of these components,
read the parts list in this manual carefully. The
use of substitute replacement parts that do not
have the same safety characteristics as
specified in the parts list may create shock, fire,
or other hazards.
2. Before returning the set to the customer,
always do an AC leakage current check on the
exposed metal parts of the cabinet, such as
terminals, screw heads, and metal overlays, to
be sure the set is safe to operate danger of
electrical shock. Plug the AC line cord directly
into a 120 V AC outlet(USA Version) or 230 V
AC outlet(EU Version). (Do not use a line
isolation transformer during this check.) Be sure
your AC voltmeter has a sensitivity of 5000 Ω
per volt or greater. Then connect a 1500 Ω10
watt resistor, paralleled by a 0.15 µF 150 V AC
capacitor, between a known good earth
ground(such as a water pipe, or conduit) and
the exposed metallic parts, one at a time.
Measure the AC voltage across the combination
of a 1500 Ωresistor and a 0.15 µF capacitor.
Reverse the AC plug at the AC outlet and
repeat AC voltage measurements for each
exposed metalic part. Voltage measured must
not exceed 0.75 V RMS. This corresponds to
0.2 mA AC. Any value exceeding this limit
constitutes a potential shock hazard and must
be corrected immediately.

2
Measuring methods are based on IHF and IEC standard 268-3
Measurements conditions,unless otherwise noted :
Output resistive load = (6) ohms / Both channel driven
Tone Direct ON , Other SW's : OFF
Nominal input level : 5mV for MM, 0.5mV for MC, 500mV for general purpose inputs
Power figures should be kept minimum 10min. between 15 and 35
Terminator : 100ohm for MC, 1kohm for MM and general purpose inputs
Filter : IHF-A filter, R/O = Rated Output
Power supply : 120V/60Hz(A), 230V/50Hz(AUS/RDS), 220V/60Hz(K)
FRONT AMP SECTION * SPKR LEVEL : ALL 0dB * SPK SIZE : LLLLY
* EXT IN INPUT * TONE OFF
No. DESCRIPTION INPUT FREQ. REMARK UNIT LIMIT L/R NOMINAL
L/R
1 INPUT SENSITIVITY EXT IN INPUT 1kHz R/O mV 300±50 300±30
2 TOTAL HARMONIC DISTORTION EXT IN INPUT 40Hz R/O-3dB 0.12 0.08
(STEREO IN) 1kHz R/O-3dB 0.12 0.08
20KHz R/O-3dB 0.2 0.12
3 CONTINUOUS AVERAGE POWER EXT IN INPUT 40Hz (6)ohms W 85 90
at 1% THD (STEREO IN) 1kHz W 95 100
20KHz W85 90
4 S/N RATIO, INPUT SHORT
IHF-A FILTER
5 FREQUENCY RESPONSE (-3dB) EXT IN INPUT 1W/1KHz Ref. Hz~kHz 20~50 20~55
CENTER AMP SECTION (FRONT CENTER) * SPKR LEVEL : ALL 0dB * SPK SIZE : LLLLY
* EXT IN INPUT * TONE OFF
No. DESCRIPTION INPUT FREQ. REMARK UNIT LIMIT NOMINAL
1 INPUT SENSITIVITY EXT IN INPUT 1kHz R/O mV 300±50 300±30
2 TOTAL HARMONIC DISTORTION EXT IN INPUT 40Hz R/O-3dB 0.12 0.08
(STEREO IN) 1kHz R/O-3dB 0.12 0.08
20KHz R/O-3dB 0.2 0.12
3 CONTINUOUS AVERAGE POWER EXT IN INPUT 40Hz (6)ohms W 85 90
at 1% THD (STEREO IN) 1kHz W 95 100
20KHz W85 90
4 S/N RATIO, INPUT SHORT EXT IN INPUT
IHF-A FILTER
5 FREQUENCY RESPONSE (-3dB) EXT IN INPUT 1W/1KHz Ref. Hz~kHz 20~50 20~55
EXT IN INPUT 1KHz R/O
1KHz R/O
SPECIFICATION
dB 85 90
dB 85 90

3
SURROUND AMP SECTION * SPKR LEVEL : ALL 0dB * SPK SIZE : LLLLY
* EXT IN INPUT * TONE OFF
No. DESCRIPTION INPUT FREQ. REMARK UNIT LIMIT L/R NOMINAL
L/R
1 INPUT SENSITIVITY EXT IN INPUT 1kHz R/O mV 300±50 300±30
2 TOTAL HARMONIC DISTORTION EXT IN INPUT 40Hz R/O-3dB 0.12 0.08
(STEREO IN) 1kHz R/O-3dB 0.12 0.08
20KHz R/O-3dB 0.3 0.2
3 CONTINUOUS AVERAGE POWER EXT IN INPUT 40Hz (6)ohms W 85 90
at 1% THD (STEREO IN) 1kHz W 95 100
20KHz W85 90
4 S/N RATIO, INPUT SHORT EXT IN INPUT
IHF-A FILTER
5 FREQUENCY RESPONSE (-3dB) EXT IN INPUT 1W/1KHz Ref. Hz~kHz 20~50 20~55
SURROUND BACK AMP SECTION * SPKR LEVEL : ALL 0dB * SPK SIZE : LLLLY
* EXT IN INPUT * TONE OFF
No. DESCRIPTION INPUT FREQ. REMARK UNIT LIMIT L/R NOMINAL
L/R
1 INPUT SENSITIVITY EXT IN INPUT 1kHz R/O mV 300±50 300±30
2 TOTAL HARMONIC DISTORTION EXT IN INPUT 40Hz R/O-3dB 0.12 0.08
(STEREO IN) 1kHz R/O-3dB 0.12 0.08
20KHz R/O-3dB 0.3 0.2
3 CONTINUOUS AVERAGE POWER EXT IN INPUT 40Hz (6)ohms W 85 90
at 1% THD (STEREO IN) 1kHz W 95 100
20KHz W85 90
4 S/N RATIO, INPUT SHORT EXT IN INPUT
IHF-A FILTER
5 FREQUENCY RESPONSE (-3dB) EXT IN INPUT 1W/1KHz Ref. Hz~kHz 20~50 20~55
dB 85
R/O dB
1KHz R/O
85 90
90
1KHz

4
SUBWOOFER SECTION * SPKR LEVEL : ALL 0dB * SPK SIZE : LLLLY
* EXT IN INPUT * TONE OFF
No. DESCRIPTION INPUT FREQ. REMARK UNIT LIMIT L/R NOMINAL
L/R
1 PRE OUTPUT LEVEL SUB-CH(300mV) 30Hz VOL max. V 3.5±1.0 3.5±0.5
STEREO SECTION * SPKR LEVEL : ALL 0dB * SPK SIZE : LLLLY
* TONE OFF(TONE DIRECT)
No. DESCRIPTION INPUT FREQ. REMARK UNIT LIMIT L/R NOMINAL
L/R
1 INPUT SENSITIVITY CD 1kHz mV 300±50 300±30
2 CHANNEL BALANCE CD 1kHz R/O TO -40dB dB 3 2
3 RESIDUAL NOISE 1kHz VOL min. mV 2.0 1.5
(INPUT SHORT) 1kHz VOL max. mV
4 TOTAL HARMONIC DISTORTION (40)Hz R/O-3dB 0.12 0.08
CD(300mV) 1kHz 0.12 0.08
(20)KHz 0.2 0.12
5 CONTINUOUS AVERAGE POWER (40)Hz (6)ohms W 85 90
at 1% THD CD 1kHz W 95 100
(20)KHz W85 90
6 S/N RATIO, IHF-A FILTER 1kHz R/O dB 85 90
1kHz 1W dB
7 CHANNEL SEPARATION 100Hz R/O-3dB dB 50 65
CD(300mV) 1kHz dB 55 65
10kHz dB 40 50
8 FUNCTION CROSSTALK 1kHz dB 60 65
(INPUT SHORT) 10kHz dB 40 45
9 FREQUENCY RESPONSE (-3dB) CD(300mV) 1W Hz~kHz 20~50 20~55
10 TONE CONTROL , ±(10)dB 100Hz 1W dB ±10(±3) ±10(±2)
(TONE ON) 10kHz dB ±10(±3) ±10(±2)
11 HEADPHONE OUTPUT(STEREO)
H/P = 64ohms
12 CINEMA EQ(SPK : LLLY) SUB-CH(300mV) 10kHz 1W dB -4.5±1.5 -4.5±1
3.0±0.5CD(300mV) 1kHz R/O V 3.0±1.0
CD
CD
CD(300mV)
CD TAPE IN

5
Impedance : Video output level at 75 ohm
Test Equipment : SCOPE,VN30A1
DISC : TDV - 540 TEST DISC (ABEX)
MEASUREMENT POSITION : AT MONITOR OUT
No. INPUT REMARK UNIT LIMIT NOMINAL
1 WHITE 100% C-VIDEO Vp-p 1±0.4 1±0.2
2
HPF 100KHz
LPF 4.2MHz
SC Trap ON
Color S/N HPF 10KHz
* ALC : OFF LPF 500KHz
* RANGE : AUTO
* BOTH
No. INPUT REMARK UNIT LIMIT NOMINAL
1 WHITE 100% Vp-p 1±0.4 1±0.2
2
HPF 100KHz
LPF 4.2MHz
SC Trap ON
Color S/N HPF 10KHz
* ALC:OFF LPF 500KHz
* RANGE:AUTO
* BOTH
40 45
VIDEO SECTION
(1) INPUT : C-VIDEO OUTPUT : C-VIDEO
DESCRIPTION
OUTPUT LEVEL
dB
S/N RATIO
WHITE 50% TITLE2 CHAP.4 dB
(2) INPUT : S-VIDEO OUTPUT : C-VIDEO
40 45
Brightness S/N
(VN30A1)
MAGENTA TITLE2 CHAP.17
AM dB 40 45
PM
DESCRIPTION
OUTPUT LEVEL
S/N RATIO
WHITE 50% TITLE2 CHAP.4
Brightness S/N
(VN30A1)
dB 40 45
MAGENTA TITLE2 CHAP.17
AM dB 40 45
PM dB 40 45

6
No. INPUT REMARK UNIT LIMIT NOMINAL
1 WHITE 100% Vp-p 1±0.4 1±0.2
2
No. INPUT REMARK UNIT LIMIT NOMINAL
1 WHITE 100% Vp-p 1±0.4 1±0.2
2
No. INPUT REMARK UNIT LIMIT NOMINAL
WHITE 100% Y Vp-p 1±0.4 1±0.2
R-Y Vp-p 0.5±0.2 0.5±0.1
B-Y Vp-p 0.5±0.2 0.5±0.1
No. INPUT REMARK UNIT LIMIT NOMINAL
WHITE 100% Y Vp-p 1±0.4 1±0.2
R-Y Vp-p 0.5±0.2 0.5±0.1
B-Y Vp-p 0.5±0.2 0.5±0.1
No. INPUT REMARK UNIT LIMIT NOMINAL
WHITE 100% Y Vp-p 1±0.4 1±0.2
R-Y Vp-p 0.5±0.2 0.5±0.1
B-Y Vp-p 0.5±0.2 0.5±0.1
(3) INPUT : C-VIDEO OUTPUT : S-VIDEO
DESCRIPTION
OUTPUT LEVEL
BURST LEVEL Color Bar Play (Title 2,Chap 1) C-VIDEO mVp-p 282±80 282±50
(4) INPUT : S-VIDEO OUTPUT : S-VIDEO
DESCRIPTION
OUTPUT LEVEL
BURST LEVEL Color Bar Play (Title 2,Chap 1) C-VIDEO mVp-p 282±100 282±80
(5) INPUT : C-VIDEO OUTPUT : COMPONENT(A/K ONLY)
DESCRIPTION
1 OUTPUT LEVEL Color Bar Play (Title 2,Chap 1)
(6) INPUT : S-VIDEO OUTPUT : COMPONENT(A/K ONLY)
DESCRIPTION
1 OUTPUT LEVEL Color Bar Play (Title 2,Chap 1)
(7) INPUT : COMPONENT OUTPUT : COMPONENT
DESCRIPTION
1 OUTPUT LEVEL Color Bar Play (Title 2,Chap 1)

7
DOLBY DIGITAL INPUT SECTION
INPUT : COAXIAL (CD DIGITAL)
SURROUND MODE : DOLBY DIGITAL
VOLUME POSISTION : 55dB
AT SPEAKER OUT Disc:LD VER 1.0
SPEC
NOMI. LIMIT
1 OUT PUT LEVEL FRONT 1KHz 8 ,12 V 9.5±1 9.5±2
Disc All CH 0dB CENTER 1KHz 10 V 9.5±1 9.5±2
SPK MODE:LLLY,BACK-NO SURR 1KHz 14,16 V 9.5±1 9.5±2
S/W 30Hz 18 V
%
%
%
%
1.0±0.5 1.0±0.8
2 T.H.D FRONT 1KHz 38 0.3 0.5
Disc 0dB CENTER 1KHz 38 0.3 0.5
LPF(20KHz) SURR 1KHz 38 0.3 0.5
SPK MODE:LLLY,BACK-NO S/W 30Hz 18 0.25 0.3
3 S/N FRONT 1KHz 6dB 65 60
LPF(20KHz) CENTER 1KHz 6dB 65 60
JIS-A FILTER,Disc -20dB SURR 1KHz 6dB 65 60
SPK MODE:LLLY,BACK-NO S/W 30Hz 18 dB 65 60
4 DYNAMIC RANGE FRONT 1KHz 38 dB -11±1 -11±2
CENTER 1KHz 38 dB -11±1 -11±2
SURR 1KHz 38 dB -11±1 -11±2
S/W 30Hz 18 dB 0±10±2
5 DIALOG FRONT 43 dB -10±0.5 -10±1
NORMALIZATION CENTER 43 dB -10±0.5 -10±1
SURR 43 dB -10±0.5 -10±1
S/W 43 dB -10±0.5 -10±1
6 OUT PUT CONFIG 1 FRONT 1KHz 38(ref)
SPK MODE : SSSY,BACK-NO 20
Ref : 1KHz 0dB CENTER 1KHz 38(ref)
20
SURR 1KHz 38(ref)
20
Ref : 30Hz 0dB S/W 30Hz 18(ref)
22
7 OUT PUT CONFIG 2 FRONT 1KHz 38(ref)
SPK MODE : LSSN,BACK-NO 18
8 DOWNMIXING TEST CENTER 1KHz 10(ref)
SPK MODE : LSSY,BACK-NO C NO
SURR.L 1KHz 14
LS NO
SURR.R 1KHz 16
RS
SY:ON
NO
FRONT 1KHz 6(ref)
-17±3
No. DESCRIPTION INPUT FREQ.
-17±3
-17±3
6.0±2
dB 7.5±1
dB
5.5±1
dB
dB
dB
CHAP
-17±1dB
UNIT
dB -3±0.5 -3±1
-17±1
-17±1
dB -3±0.5
dB -3±0.5
6.0±1
5.5±2
7.5±2
-3±1
-3±1

8
DOLBY-EX INPUT SECTION
INPUT : COAXIAL, CD DIGITAL
SURROUND MODE : DOLBY-EX
VOLUME POSISTION : 55dB
AT SPEAKER OUT SPK MODE L,L,L,Y,BACK-L DOLBY-EX TEST Disc(TRACK 7)
SPEC
NOMI. LIMIT
1 OUT PUT LEVEL
Disc : DOLBY-EX -23dB
LLLY,BACK - L
2 T.H.D
Disc : DOLBY-EX -23dB
LPF(20KHz)
LLLY,BACK - L
3 S/N
Disc 0dB,JIS "A"
LPF(20KHz)
DTS INPUT SECTION
INPUT : COAXIAL, CD DIGITAL
SURROUND MODE : DTS
VOLUME POSISTION : 55dB
AT SPEAKER OUT SPK MODE L,L,L,Y,N DTS TEST Disc(TRACK 9,10,11,12,13,14,15)
SPEC
NOMI. LIMIT
1 OUT PUT LEVEL FRONT 1KHz 10,11 V10±110±2
Disc : DTS 0dB CENTER 1KHz 14 V10±110±2
LLLY,BACK -NO SURR 1KHz 12,13 V10±110±2
S/W 30Hz 15 V
%
%
%
%
1.0±0.6 1.0±0.8
2 THD FRONT 1KHz 10,11 0.3 0.5
Disc : DTS 0dB CENTER 1KHz 14 0.3 0.5
LPF(20KHz) SURR 1KHz 12,13 0.3 0.5
LLLY,N BACK -NO S/W 30Hz 15 0.3 0.5
3 S/N FRONT 1KHz 10,11 dB 65 60
Disc 0dB,JIS "A" CENTER 1KHz 14 dB 65 60
LPF(20KHz) SURR 1KHz 12,13 dB 65 60
LLLY,N S/W 30Hz 15 dB 65 60
4 DTS+NEO6 FRONT 1KHz 9V 1.0±0.2 1.0±0.4
OUTPUT LEVEL CENTER 1KHz 9V 1.0±0.2 1.0±0.4
700±70 700±100BC 1KHz 7 mV
65 60
BC 1KHz 7 0.3 0.5
TRACK UNIT
BC 1KHz STOP dB
%
No. INPUT FREQ.DESCRIPTION
DESCRIPTION UNITNo. INPUT FREQ. TRACK
Disc:ALL CH(1KHz,-20dB) SURR 1KHz 9mV 75±20 75±30
LLLY,BACK-Y (L 2CH) S-BACK 1KHz V 1.0±0.2 1.0±0.4

9
Measuring methods in confirmity with IEC standard 315
Measurements condition FM : Ref. frequency = ( 98.1MHz), Audio frequency = 1KHz
Reference level = 1mv on (75ohms, 300ohms) Deviation : Filter = B.P.F at STEREO and MONO
Test Point:TP1 = 90.1MHz,TP2 = 98.1MHz, TP3 = 106.1MHz(100KHz STEP)
MOD : MONO = 75kHz, STEREO = 67.5kHz ±7.5kHz (A)
MONO = 40kHz, STEREO = 40kHz ±4kHz (AUS/RDS/K)
Power supply : 120V/60Hz(A), 230V/50Hz(AUS/RDS), 220V/60Hz(K)
FM SECTION
NOMI. LIMIT
1 TUNING COVER RANGE LOW ~ HIGH MHz
STEP (A/K) AUTO/MANUAL KHz
(AUS/RDS) AUTO/MANUAL KHz
2 USABLE SENSITIVITY TP 1 dBu 12 15
S/N = 30dB (A) TP 2 dBu 12 15
S/N = 26dB (AUS/RDS/K) TP 3 dBu 12 15
3 AUTO STOP LEVEL dBu 25±625±8
4 S/N RATIO IHF "A" MONO dBu 55 50
STEREO dBu 50 45
5 T.H.D MONO 1KHz 0.7 1.2
STEREO 1KHz 1.0 1.5
6OVER LOAD DISTORTION(120dBu, 75KHz) MONO Db 2 3
7STEREO SEPARATION FILTER = B.P.F 250Hz dBu 30 25
MAIN 90%, PILOT 10% (A) 1KHz dBu 30 25
MAIN 53.5%, PILOT 10% (AUS/RDS/K) 6.3KHz dBu 20 15
8 FREQUENCY RESPONSE
75us, -3dB (A)
50us, -3dB (AUS/RDS/K)
9 IF REJECTION (A) dB 65 60
(AUS/RDS/K) dB 75 70
10 IMAGE REJECTION (A) dB 20 18
(AUS/RDS/K) dB 75 70
11 AM SUPRESSION (AT AM 30% 1KHz) dB 40 35
12 OUPUT LEVEL MONO (A) 500±100 500±150
(AUS/RDS/K) 280±100 280±150
13 RDS SENSITIVITY TP2 dBf 30 35
TUNER SECTION
87.5~108
100 / 100
50 / 50
SPEC
UNITDESCRIPTIONNo.
TP2 Hz 60~8K 70~7K
TP 1
TP 3
MONO mv rms

10
AM SECTION
Measurements condition AM - MW : Radio. frequency = 1000/999KHz , Audio frequency = 400Hz
Reference level = (74dBu/m),(50)ohms Modulation = ( 30 )%
Test Point : MW TP 1 = (594)KHz , TP 2 = (999)KHz , TP 3 = (1404)KHz
NOMI. LIMIT
1 TUNING COVER RANGE (A) LOW~HIGH MW KHz
(AUS/RDS/K) LOW~HIGH MW KHz
STEP (A) AUTO/MANUAL KHz
STEP (AUS/RDS/K) AUTO/MANUAL KHz
2 USABLE SENSITIVITY TP 1 dB u/m 63 65
S/N = 20dB TP 2 dB u/m 63 65
TP 3 dB u/m 63 65
3 S/N RATIO
(100)dB u/m, (30 )% MOD
4 T.H.D
74dB u/m, 30% MOD
5 OVER LOAD DISTORTION
100dB u/m ,80% MOD
6 FREQUENCY RESPONSE
(at 74dB u/m, 400Hz)-NO FILTER
7 SELECTIVITY AT SN:
20dB, ±10KHz(A)
20dB, ±9KHz(AUS/RDS/K)
8 AGC FIGURE OF MERIT
(at 100dB u/m)
9 IMAGE REJECTION TP 3 dB 28 25
10 WHISTLE MODULATION
(74dBu/m, 900KHz)
11 TUNED LEVEL 1000KHz (A)
999KHz (AUS/RDS/K)
12
13
OUTPUT LEVEL 74dB u/m, (30 )% MOD mv rms 200±100 200±150
10 / 10
520~1710
No. DESCRIPTION UNIT
SPEC
TP 2 dB
%
%
35 30
TP 2 2 3
TP 2 310
20
AT-6dB Hz 80 ~ 2K 100 ~ 1.8K
2IF dB
TP 2 dB
TP 2 dB
522 ~ 1611
9 / 9
dB u/m 55±10 55±15
10 15
50 40
23
55±10 55±15dB u/m
999KHz (AUS/RDS/K)
AUTO STOP LEVEL 1000KHz (A)

Model No. : RD-7502
11
BLOCK DIAGRAMS (VIDEO - I)

Model No. : RD-7502
12
BLOCK DIAGRAMS (AUDIO - II)

13
WIRING DIAGRAM
Model No. : RD-7502
PCB7 (ST-BY)
PCB6 (HDMI)
PCB5 (S-C VIDEO)
PCB3 (DSP)
TUNER ASS'y
PCB1 (MAIN)
PCB4 (AMP)
PCB2 (FRONT)
PCB2-1 (FUNC)
PCB2-3
(H/P)
PCB2-4
(POWER SW)
PCB2-2
(AUTO SETUP)

14
100 99 98 97 96 95 94 93 92 91 90 89 88 87 86 85 84 83 82 81
180
279
378
477
576
675
774
873
972
10 71
11 70
12 69
13 68
14 67
15 66
16 65
17 64
18 63
19 62
20 61
21 60
22 59
23 58
24 57
25 56
26 55
27 54
28 53
29 52
30 51
31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
O.DRAIN O.DRAIN
MB90F488PBF-GE1LQFP : IC402
1. Pin Description
PROTECTION
AK4588_PD
AK4588_CDTO
AK4588_CE
DSP_MUTE
DSP_SDOUT
MODE SETTING
P81 P80 MD2 MD1 MD0
LL L HH
LH H H L
RED COLOR:These pins must be fixed.
FL/NJW1197_CLK
FL/NJW1197_DATA
OSD_CE
CV_MUTE
SUR_MUTE
COMP_DET
TUNED
PLL_CE
RDS_CLK
RDS_DATA
NJW1197_LATCH
Avcc
POWER DOWN
CODEC/DSP_SCCLK
TA1270_SCL
BU2090_CLK
Vss
HP RLY
UPGRADE
CODEC/DSP_SCDIN
M24C08_SDA
M24C08_SCL
NORMAL
RMC
YELLOW COLOR:+5V Interface
Vcc5:+5V
Vcc3=Avcc=AVRH:+3V3
VOL_UP FUN_DN FUN_UP XM_DACRST
ST/BY_LED
VOL_DN
MODE
X1A
DSP_RDY
DSP_CE
MB90F488
FL B+ SW/ST BY RLY
X1 X0
VSINC_IN
C_DET
SV_DET
TA1270_SDA
SV_MUTE
BU2090_DATA
OSD_DATA
DATA OUT
PLL_DATA
PLL_CLK
MD1
NJW1197_MUTE
MD2
XM/UPGRADE_TX
P81
F_RLY
AVRH
MD0
P80
SET_OPTION
BS_RLY
C_RLY
Vss
STEP_OPTION
Avss
KEY1 KEY2 KEY3
SUR_RLY
XM_DACMS XM_DACMDI FL_CE HDMI_S3 HDMI_S2 XM_POWER HDMI_HPD XM_DACMUTE
SW_MUTE
XM/UPGRADE_RX
C_MUTE
F_MUTE
DIGILINK
Vcc5
BS_MUTE
/RST
X0A
DSP/FLASH_RST
XM_DACMC
10MHZ
Vcc3 Vss XM_RESET
CIRCUIT DESCRITION
Model No. : RD-7502
RAM
ROM
µDMA
8
2
X0, X1, RST
X0A, X1A
MD2, MD1, MD0
SIN0
SOT0
SCK0
SIN1, SIN2
SOT1, SOT 2
SCK1, SCK2
AV CC
AVRH
AV
SS
ADTG
AN0
to AN7
AIN0, AIN1
BIN0, BIN1
ZIN0, ZIN1
PPG0, PPG1
PPG2, PPG3
PPG4, PPG5
888888888
P00
P07
P10
P17
P20
P27
P30
P37
P40
P47
P50
P57
P60
P67
P70
P77
P80
P87
8
P90
P97
4
PA0
PA3
IN0, IN1
OUT0, OUT1,
OUT2, OUT3,
OUT4, OUT5
CS0, CS1,
CS2, CS3
TIN0
TOT0
IRQ0 to IRQ7
8
SCL
SDA
EXTC
MT00
MT01
PWC0
PWC1
PWC2
Clock control
Circuit
CPU
F
2
MC16LX series core
Interrupt controller
8/16 bit PPG
8/16 bit U/D counter
µPG
Chip select
Input/output timer
16 bit input capture
2ch
16 bit output compare 2ch
16 bit free-run timer
16 bit reload timer
I
2
C interface
External interrupt
UART
I/O extended serial
interface 2ch
A/D converter
( 10 bit )
PWC 3ch
I/O port
to to to to to to to to to to to
Communication
prescaler
F
2
MC-16LX Bus
: Only MB90485 series
2. Blcok Diagram

15
3. Pin Functions
Pin No. Symbol Description
1 FL_CLK Clock signal output for PT6315.
2 FL_DATA Data signal output for PT6315.
3 FL_SW/ST_BY RLY Output to "FL_B+ ON/OFF" (At "H", it is active)
4 ST/BY_LED Output to drive STAND-BY LED(At "H", it is active)
5 H/P_RLY Output to "H/P Relay ON/OFF" (At "H", it is active)
6 NC Not used!
7 BU2090_CLK Clock signal output for BU2090
8 BU2090_DATA Data signal output for BU2090
9 DIGILINK Data in/out for controlling other set.
10 C_DET Input for detecting "Composite-Video input" condition(At "L", it is active)
11 AVSS GROUND
12 CV_MUTE Output for C-VIDEO output mute(At "H", it is active)
13 SV_DET Input for detecting "S-Video input" condition(At "L", it is active)
14 SV_MUTE Output for S-VIDEO output mute(At "H", it is active)
15 COMP_DET Input for detecting "Component Video input" condition(At "L", it is active)
16 COMP_MUTE Output for COMPONENT-VIDEO output mute(At "H", it is active)
17 TA1270_SCL Serial data clock signal output for "TA1270BF"
18 TA1270_SDA Serial data signal output for "TA1270BF"
19 CENTER_RLY Output to "Center Relay ON/OFF" (At "H", it is active)
20 BS_RLY Output to "Surroundback Relay ON/OFF" (At "H", it is active)
21 NC Not used!
22 NC Not used!
23 VCC5 +5V power supply
24 SW_MUTE Output for subwoofer channel mute(At "L", it is active)
25 BS_MUTE Output for surround back channel mute(At "L", it is active)
26 S_MUTE Output for surround channel mute(At "L", it is active)
27 XM/UPGRADE_RX Data signal input for XMDTIC
28 XM/UPGRADE_TX Data signal output for XMDTIC
29 C_MUTE Output for center channel mute(At "L", it is active)
30 F_MUTE Output for front channel mute(At "L", it is active)
31 FRONT_RLY Output to "Front Relay ON/OFF" (At "H", it is active)
32 SUR_RLY Output to "Surround Relay ON/OFF" (At "H", it is active)
33 NC Not used!
34 NC Not used!
35 AVCC +3.3V power supply
36 AVREF +3.3V power supply
37 AVSS GROUND
38 KEY1 Data input for key1 scan.
39 KEY2 Data input for key2 scan.
40 KEY3 Data input for key3 scan.
41 STEP_OPTION Input for selecting the frequency ranges steps of FM and AM
42 VSS GROUND
43 SET_OPTION Input for selecting the model option.
44 NJW1197_DATA Data signal output for NJW1197.
45 NJW1197_CLK Clock signal output for NJW1197.
46 NJW1197_LATCH Latch signal output for NJW1197.
47 P80 UPGRADE
48 P81 UPGRADE
49 MD0 UPGRADE

16
Pin No. Symbol Description
50 MD1 UPGRADE
51 MD2 UPGRADE
52 KEY3_INTERRUPT INTERRUPT for KEY3.
53 TUNED Input for detecting "TUNED" condition(At "L", it is active)
54 PLL_DATA Data signal output for "LC72131"
55 PLL_CLK Clock signal output for "LC72131"
56 PLL_DATAIN Input from "LC72131"
57 RDS_CLK Clock signal input from "BU1924"
58 PLL_CE Output for chip enable of "LC72131"
59 RDS_DATA Input for RDS data from "BU1924"
60 NJW1197_MUTE MUTE signal output for NJW1197.
61 M24C08_SDAT Input/output for M24C08.
62 M24C08_SCLK Clock signal output for M24C08.
63 NC Not used!
64 RMC Input for remocon data.
65 NC Not used!
66 CODEC/DSP_SCDIN Data signal output for AK4588/DA607
67 CODEC/DSP_SCCLK Clock signal output for AK4588/DA607
68 DSP_CE Output for chip enable of da607
69 DSP_RDY output for ready signal to da607
70 DSP/FLASH_RST Reset signal output to da607/M29W400
71 DSP_SDOUT Chip select signal output to CS49326
72 DSP_MUTE Output for surround channel mute(At "L", it is active)
73 AK4588_CE Output for chip enable of AK4588
74 AK4588_CDTO Input for AK4588 Control Data Output
75 AK4588_PD Output for AK4588 Power Down
76 PROTECTION Input for detecting "PROTECTION" condition
77 RESET Input for resetting the CPU(At "L", it is active)
78 POWER DOWN Input for power down.
79 X1A UPGRADE
80 X0A UPGRADE
81 VSS Ground
82 XIN Input for 10MHz crystal oscillator
83 XOUT Output for 10MHz crystal oscillator
84 VCC3 +3.3V power supply
85 XM_IRQ Input for Interrupt request of XMDT IC.
86 XM_COMMSEL Output for commend mode select of XMDTIC.
87 XM_RESET Output for resetting the XMDTIC(At "H", it is active)
88 XM_DAC_PDN Output for power down of AK4385.
89 XM_DAC_CSN Output for chip select of AK4385.
90 XM_DAC_CCLK Output for control clock of AK4385.
91 XM_DAC_CDTI Output for control data of AK4385.
92 XM_DAC_MUTE Output for analog output mute (At "H", it is active)
93 HDMI_S3 Output for HDMI Input select of TMDS341
94 HDMI_S2 Output for HDMI Input select of TMDS341
95 HDMI_HPD Output for HPD ON/OFF
96 VOL. DOWN Input for main volume down.
97 VOL. UP Input for main volume up.
98 FUNC_DOWN Input for main function down.
99 FUNC_UP Input for main function up.
100 FL_CE Output for chip enable of PT6315

17
1. Electrical specification
Local OSC
Frequency cover range
Standard supply voltage
FM Antenna Impedance
AM Loop Antenna
2. Electrical Characteristics
AF Output Level
Auto Stop Level
Stereo Separation 1kHz
AF Output Level
Auto Stop Level
3. Adjust Point
98.1 60
75 ohm unbalance
40
FM
47kΩLoad 98.1 60
MW 47kΩLoad 999 74
--
30 180 ±60
280±100 mV
25 ±6 dBu
1-3
1-4
No.
9.5uH ( 1kHz ) : S0160BL-25
12 +/-0.5V
Above the receiving Frequency
M W F M
522 ~1620kHz 87.5 ~ 108.0MHz
ITEMS SPECIFICATION
1-1
kHz,%dBu
TEST
CONDITION T.P.
1-5
Adjustment
1-2
SVR01
UNITSpecification
No.
Non Adjust
98.1 --
TEST ITEMS MOD.T.L.
dBu999
TUNER ALIGNMENT
SVR02
Non Adjust30 55 ±15
25 min dB
mV Non Adjust

18
Ref No.
Power On Failure A) AC-Cord check.
1. FLT does not light up. B) Power Trans (Main/ST-BY) check.
2. ST-BY LED does not light up. C) Fuse's disconnection check. F ( 300,301)
D) Connector's disconnection or disjunction.
Change or close insertion of the connector. CN301,CP514
E) Inferior ST-By switch. SW(700)
F) VFD Driver I.C & Resonator check. I.C701 SC16315
1. VFD Driver I.C VCC(+3.3)V check. I.C701 Pin No13
2. VFD Driver clock pulse check. I.C701 Pin No5
Fuse Disconnection. A) Inferior transformer.
(Power On) B) AMP drive TR out. (POWER TR) Q206( FL, FR, C, SL, SR, SBL, SBR )
C) AMP drive TR out. ( POWER TR ) Q205 ( FL, FR, C, SL, SR, SBL, SBR )
D) voltage check.
1. B+ ( 40 )V, B- ( 40 ) V
Key Disorder. A) Key's being pushed check. SW ( 700 )
B) Key signal input components inferior.
C) Key data check. I.C402 Pin No. ( 38,39,40 )
D) µ-COM I.C or Resonator inferior.
1. µ-COM IC VCC +3.3V check. I.C402 Pin No. ( 23,35,36,84 )
2. µ-COM clock pulse check. I.C402 Pin No. ( 82,83 )
Power Off in 2~3 sec. A) Regulator I.C out. I.C 300 (LM1117S_3.3V)
after Power On. 1. Signal IN/OUT check.
B) Drive transistor out. ( POWER TR ) Q205 ( FL, FR, C, SL, SR, SBL, SBR )
Q206 ( FL, FR, C, SL, SR, SBL, SBR )
C) Protection circuit check.
1. Output DC check.
2. µ-COM I.C protection terminal check. u-COM Pin No. ( 76 )
D) Connector's disconnection or disjunction CP (411)
E) SLEEP MODE cancellation.
Bump Sound A) FRONT Mute transistor's out and inferior. Q ( 511 )
(During input-select switch's change.) µ-Com front mute control PORT check. IC501 Pin No. ( 30 )
B) CENTER Mute transistor's out and inferior. Q ( 509 )
µ-Com center mute control PORT check. IC501 Pin No. ( 29 )
C) SURROUND Mute transistor's out and inferior. Q ( 510 )
µ-Com surround mute control PORT check. IC501 Pin No. ( 26 )
D) SURROUND BACK Mute transistor's out and inferior. Q ( 507 )
µ-Com surround mute control PORT check. IC501 Pin No. ( 25 )
Sounds from Speaker when A) HEADPHONE JACK connection inferior. CN702
Head phone's connected.
Bass / Treble Control Failure. A) Bass volume check. I.C401
1. Resister/Capacitor correction figure check. I.C401 PIN No. ( 13,14)
2. BASS VR's property inferior.
TROUBLESHOOTING
Cause and RemedySymptom

19
Ref No.
Cause and RemedySymptom
B) TONE I.C check. I.C No. ( 401 )
1. Signal IN/OUT terminal check.
2. I.C voltage check. ( +7.5)V, ( -7.5 )V I.C PIN No. ( 16,18 )
3. I.C CLK/DATA/STB/MUTE I.C PIN No. (69,68,70,71)
AMP Sound Dead. A) Signal Mute TR's inferior. Q 507,509,510,511
1. "LEFT" Channel dead. B) Connector disconnection & disjunction. CP ( 411)
2. "RIGHT" Channel dead. Change or close insertion of the connector.
3. "CENTER" Channel dead. C) Speaker wire's disjunction.
4. "REAR" Channel dead. Close insertion of the speaker wire.
5. "REAR CENTER" Channel dead. D) Signal switching IC check. I.C No. ( 401 )
1. I.C voltage check ( +7.5 )V, ( -7.5 )V I.C Pin No. ( 16,18)
2. Switching I.C control data check. I.C PIN No. (69,68,70,71)
3. Switching I.C signal IN/OUT check.
AC-3/DTS Failure. A) I.C Regulator check.
(DSP Sound Mode) DIGITAL IN + ( 5 )V, ANALOG IN + ( 5 )V
IN + ( 3.3)V, OUT + ( 1.2 )V I.C No. ( 801 )
IN + ( 5 )V, OUT + ( 3.3 )V I.C No. (807 )
B) DIR check. I.C800
1. OSC check. X-TAL ( 800 )
2. RMCK, RBCK, RLRCK, RDATA Check. I.C Pin No. ( 09) ( 15 ) ( 16 ) ( 17 )
3. Micom Interface Port Check. I.C Pin No. ( 66,67,73,74,75 )
C) DSP Check. I.C No. ( 805)
1. INTREQ Check. I.C Pin No. ( 108 )
2. LRCK Check. I.C Pin No. ( 16,107 )
3. Micom Interface Port Check. I.C Pin No. ( 66,67,68,69,70,71)
4. SDATA 1, 2, 3,4 Check. I.C Pin No. ( 92,94,95,97 )
D) D/A Check. I.C No. ( 800)
1. LRCK/BCK/SDATA check. I.C Pin No. ( 17,18,19)
2. Signal out check. I.C Pin No. ( 49,47,45,43,41,39,37,35 )
Video Output Dead. A) Video Regulator voltage check.
1. DC voltage check. B+ ( 9 )V, B+ ( 5 )V, B- ( -5)V I.C No. ( 204,203,205)
B) Video selector control IC check.
1. DC voltage check. B+ ( 5 )V, B- ( -5)V IC NO(201)/IC PIN No.(7,18)
2. DC voltage check. B+ ( 5 )V, B- ( -5)V IC NO(217,218)/IC PIN No.(16,7)
3. Micom control data check. I.C Pin No. ( 7,8,17,18 )
C) Video input detect port check.
1. Micom CV, SV, COMPONENT-V detect port. I.C NO. ( 402 ) / I.C Pin No. ( 10,13,15)
Video down output Dead. A) Video voltage check.
1. DC voltage check. B+ ( 3.3)V I.C NO. ( 209 ) / I.C Pin No. (5 )
B) S-Video input signal check.
1. Yin, Cin signal check. I.C Pin No. ( 1,8 )
Video up output Dead. A) Micom Interface Port Check.
1. SCL, SDA port check. I.C NO. ( 402 ) / I.C Pin No. (17,18 )
B) C-Video Input video input signal check. I.C NO. ( 217) / I.C Pin No. (11,12,14)
S-Video Input video input signal check. I.C NO. (218) / I.C Pin No. (1,5,12,14 )
C) Component video output check. I.C NO.(201) / I.C Pin No.(20,22,24)