Sherwood RV-5050RDS User manual

SERVICE MANUAL
RV-5050RDS
STEREO A/V PRO-LOGIC RECEIVER
Sherwood Oremume mAi/DIC.VIDEC RECEIVER RV. 5050ROS
OR 2 TL OR PCAN Ran,
==
© ©
©
=cee9
=a CONTENTS «
Safety PreCAUtiONS------ere eee cere eter tet tee cece eee e eee eee 2 Exploded VIEW cece ee ccc nce cen cence cscecncceccscccanseatece 23
Specifications wales Bier care Madicsive’s SSbrpe station Suse esses ewes 3 Printed Circuit Boards ----++--- ces cee cee cee cee eee eneeneees 25
Wiring Diagram ee re er ee ee 5 Mechanical Parts List --------eeceseeeee eee ceeceeceeeeeaee 31
Block Diagram eerrerrerer er er rer errr errs reer reer errr eee es 7 Electrical Parts List --------+ssseeeceeees cee ceceesseseeeees 32
Circuit Description ----++++-++-++eseese reste ee cee eee cee ee eees 9 Semiconductor Lead Identification
Alignment PrOC@dAUres cerrer ee eee cee er eee cet eee eee ees 17 & internal Diagram BG ESis ob.cia sie do wien ee ae es bade's waiea sees 38
Troubleshooting ----:eeereceeereee ee te reece eects tees ees 20 Schematic Diagrams(I, II, I. [V) --++--:eseeeeee eee 45
| G Sherwood

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
Replacement parts that have these special
safety characteristics are identified in this
manual and its supplements: electrical
components having such features are
identified by /A\ 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
AC Outlet
At 5000 Q per volt or greater sensitivity,
the reading should not exceed 0.75 V.
0.15 pF, 150 V AC
Place the probe on each exposed metalic part.
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 230 V AC outlet.
(Do not use a line isolation transformer
during this check.) Be sure your AC voltmeter
has a sensitivity of 5000 Q per volt or greater.
Then connect a 1500 2 10 watt resistor,
paralleled by a 0.15 uF 150 V AC capacitor,
between a known good earth ground (such as
a water pipe, or conduit) and the exposed
metalic is parts, one at a time. Measure the
AC voltage across the combination of a 1500
Q resistor and a 0.15 uF 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.
AC Voltmeter
Good earth ground, such as
a water pipe or conduit.

SPECIFICATIONS
FRONT AMP SECTION
Condition: DOLBY PROLOGIC off.
No.|
Description
Unit
|
Nominal
Limit
|
| 1 |RMS Output Power(mode: STEREO)
both
channels
driven
at
40
Hz-20
up
freg.,
0.7%
THD,
8
Q
load.
>82
>80
2 |Inter Modulation Distortion (60 Hz:7 du=4:1 SMPTE)
L
at
8
©
load,
80
W
output.
%
<0.05
<0.08
3
|Input
Sensitivity
PHONO!
py
|
2.8
+
0.35
2.8
+
0.4
I
at
1
Miz
freq.,
47
kQ
Impedance.
CD,ETC)
my
|
170
+
20
170
+
30
|
4
|PHONO
Input
Overload
at
1
ki
freq.,
0.5%
THD
nV
>140
>120
5 \Frequency Response;
at
8
©,
1
W
output,
30
-
15000
Hz
---------------
>
PHONO!
gp
|
RIAA
+1.0
RIAA
+1.5
|
ats
©,
80
W
output,
-3
aB-
------------------->CD,
TAPE)
Hz
|
10-60000
20-50000
|
6
[Signal
to
Noise
Ratio
IHF"A"
weighted
PHONO,
gp
=70°
|
>66
at
8
©,
1
kz,
80
W
output
CD,
AUX;
@B
>90
>
85
7
|Tone
Control
at
8 Q,
1
W
output
BASS:
100
Hz}
«GB
10+1.8
+1042
|
TREBLE:
10
kh]
oB
10+1.8
+1042
8
[Channel
Separation
at
8
Q,
80
W
output
100
Hz!
oB
>50
j
>40
Input
shorted,
CD,
TAPE
1}
oB
>50
>40
oe 10k B | >45 >35
9
{Crosstalk
at
8
O,
1
kd
freq.,
80
W
output
CD=>TAPE1|
gB
>65
>50
|
Input
shorted
TAPE=CD,|
oB
>60
>50
10
|Sub
woofer
output
at
CD,
1
kh,
170
ny
input
|
nV
900+100
|
900+150
|
11
[Headphone
output
at
1
kz,
1
W
Speaker
output
33
Q
Load]
my
|
200430
200
+
50
10
|
Total
Harmonic
Distortion
40
fz)
%
<0.05
<0.2
at
8
Q
load,
80
W
output
1kk|
%
<0.05
<0.2
20k) % | <0.2 <0.3
REAR AMP SECTION
Condition
input:
CD,
Input
level:
1
Kaz
freq.
230
nv,
Rear
level:
Max.,
Mastar
Volume:
adj.
No.|Description
Unit
|
Nominal
Limit
1
|RMS
Output
Power(1
CH.
driven
80
W)
|
at
1
iz
freq.,
8
Q
load
|
%
|
<0.8
<1
|
2
|Frequency
Response
>80-
7000)
+100
-
7000
at
1
W
output,
+3
dB,
WIDE
MODE
|
Hz
(+
500)
(+1000)
3
|Signal
to
Noise
Ratio(IHF"A”"
weighted)
Delay
time:
20
ms
DOLBY|
dB
|
265
>60
|
CENTER AMP SECTION
Condition
Input:
CD,
Input
level:
1
Wz
freq.
220
ny,
Center
level:
Max.,
Mastar
Volume:
adj.
No.|/Description
Unit
|
Nominal
|
Limit
|
1
‘RMS
Output
Power(1
CH.
driven
80
W)
aes
|
at
1
kHz
freq.,
8
©
load
|
%
<0.2
|
<0.4
2
|Frequency
Response
|
at
1
W
output,
-3
qB,
DOLBY
NORMAL}
Hz
|100-17000)
150-15000
|
|
WIDE}
Hz
|
30-
17000
50-15000
|
|
3
[Signal
to
Noise
Ratio
(IHF"A"
weighted)
NORMAL)
4B
>78
>70
|
VIDEO SECTION
(No.
Description
|
Unit
|
Nominal
Limit
|
1
[Input
Sensitivity/impedance
|
dB
|1Vp-p/75
O
+0.5
L
2
|Output
Level/impedance
[
gB
1
Vp-p/75
9
+0.5'
|
3
|Frequency
Response
5
Hz
-6
M|
4B
+2
+3
4
|Crosstalk
1.0
Wm
dB
>45
|
>40
[
5
{Signal
to
Noise
Ratio
|B
345
>40

FM SECTION
Antenna Impedance: 75 QO
AM SECTION
No./Description
Tuning Frequency Range, Step: 9 kz
Usable Sensitivity
Signal to Noise Ratio
>| Cy Fy) Go} PO]
Unit
Kz
/m
dB
%
No.|/Description Unit | Nominal Limit
1 [Tuning Frequency Range, Step: 50 kt Miz 87.5 - 108.0
2 |Usable Sensitivity df <17.2 <20.7
3 |-46 gB Quieting Sensitivity MONO] iW <3 <5
STEREO <35.8 <56.2
4
|Signal
to
Noise
Ratio
(IHF"A"
weighted)
MONO!
«B
>70 >65
=-
STEREO} aB >65 >60
5
|Total
Harmonic
Distortion
at
1
kd
freq.
MONO!}
%
<0.30
<0.50
STEREO| % <0.60 <0.90
6
/Frequency
Response
at
20
Hz-15
kh
dB
>4+2
>+3
7
|Image
Rejection
dB
>40
>35
8
|Spurious
Response
dB
>70
>60
9
|IF
Rejection
|
dB
>65
>60
10
|Alternative
Channel
Selectivity
dB
>
50
>40
11/AM
Suppression
Ratio
dB
>60
>50
12
|Stereo
Separation
100
Hz;
B
>40
>35
1k! «B >45 >40
10 Wz} GB >35 >30
13
|Auto
Stop
Error
MONO
|
apf
28+5
28+6
14
|Muting
Threshold
dbf
2845
28+6
15
|Output
Voltage
MONO)
nv
500
+
80
500
+
150
16
|RDS
Sense
@TA
ON
Level
28.1
35.8
Nominal
522 - 1611
<500
>45
<1.0
|
1
|
Tuning
Frequency
Range,
olep.
9
kip
CNS
|
2
|Usable
Sensitivity
SO
SON
Total
Harmonic
Distortion
Selectivity
i
dB
>25
>20
Image
Rejection
dB
>33
>28
<800
> 40
<i5
7 |Frequency Response
at
400
yz
freq.
0
dB,
-6
aB
Hz
80
-
2100
100
-
1800
9
|Auto
Stop
Level
dB/m
60+5
60+6
11
|Output
Voltage
400
Hz,
30%
MOD.,
@1000
rz!
nv
200+
40
200+50
=|
General
Speaker
Load
Impedance
-
-
- -
-
-
--
-------------------
5-2
r
rrr
rrr
rrr
rrr
r
rrr
8Q
Power
Consumption
-
-
-
-
-
--
-------------------------------------------------
640
W
Dimensions
(WxHxD)
--------------------------------
2-2-0025
-
ree
(17-5/16X5-1/2X13
inch)
Weight
(Net)
-----------------------------------------------------------
Power
Supplies
-
-
---------------------------
7-2-5
-rr
rrr
crc
errr
cre
Specifications and components subject to change without notic
Overall performance will be maintained or improved.
440X140X330 mm
9.85 kg
(21.72 Ibs)
230 V AC, 50 Hz

AC INPUT
POWER
TRANS
OOD00000 000
eee TRANS B’D
4001001430
CN1i04
(PCB7)
PWA SW B’D
4001001440
SPK A.B
HEADPHONE 8’ D
400 10041630
(PCB10)
CN10S
WIRING DIAGRAM
(PCB11) (PCB2)
PRE-IN OUT B’D
400 1001650
yv is
SURROUND SPK & VIDEO B’D
4001002910
CN205 cP2i0
HEAT/SINK
8beNOD
4001002360
MAIN B’'D
[dE ]
o
Cc
3
bO
oc
Oz
>
o°
ies
we
on
Oo
6YeCNO
CN221
4001004400
FRONT 8°D (PCB3)
jo]
jo]
©
=<
°
°
=
°
(°]
v
CNe1i
CN212
CNe1i3
QP
6P
4001001420
SURRE& VOL B’ D
(PCB4)
alc
A S
oO
Al
(PCBS)
i CP2i7 SP
TAPE2 B’'D
4001004620
TUNER& ROS B’ D
Model No. : RV-5050RDS
CN216
4001001610
(PCBS)
cP2i3
CP221
4001001410

ANT
n x
AM
rs |
TUNER OO
more O 0 ©
cotvep)
1 Oo ©
A TAPE 1 [ om
°o © © CO
v eset
:©
OD tapee [
MON fe)
I
(1C¢101/102)
6 I
VCR [ vcR 1 REC
°
vVCRe
—
REAR
4
I
DB ver: [
fe]
E
0 GO4066
vere
ie
REAR
MONITOR
Out
BLOCK DIAGRAM
pe RES Se Sea ee eee re ay ees toe 5
1
| rs Plo]
= START ap
' DEMODE . CECODE AbS- eo
t _
: *DA73306 LC7O73 1
\ LA1235 1
SIGNAL METER[ 1 oo Dt svu |
7 3 DATA
CLK
cE
TUNED
STEREO
a MUTE
eorora ae LA3410
ia
my [Doe
aM EM L.P.F
iA 7
ea
PRO LOGIC/Z ‘
3 STEREO x
DOLBY PRO-L.OGIC
ADAPTIVE MATAIX
NUM 2177A [(IC501)
DIGITAL
DELAY
NUU 9701
(IcSO3)
FL
CPU
(ic505)
SHIFT REGISTER
MC 14094
INPUT PaRT
SLRROUND PART
TUNER PART
MAIN PART
POWER PART
Se BALANCE O
| vou. Bae=sue: oMAINZEN
)
Tcosess N
Model No. : RV-5050RDS
RESOR KEY
—NATOR
MATRIX
DIG:
DISPLAY LINK
O RMC SENSOR | <L~ (| commences
| Y
RELAY
PEs ;
CP ij niezon
-27v '
\
REGULAT ae
FL ac 3.5v 4 ST-BY
RELAY
+12v < REGULATOR
-12V 12v -iev
+ BV Sv
FRONT AMP. 2 AMP
CENTER AMP, <A POWER
REAR amp. SUPPLY
REGULATOR Sv
POWER Sw
ac
INPUT
OC R WOOFER
OuT
L
HEAO
PROTECT
PHONE
A
©
STEREO MODE GOW X 2
SURA MODE SOW x 2
MUTE CH MUTE
B
CENTER
PRE-OuT +
DISCRETE
CENTER
AMP
CENTER SOW
PROTECT
REAR 25wx2e
DISCRETE
RESAR AMP

CIRCUIT DESCRIPTION
1C201 : uPD78044AGF-152 (8bit CMOS Microprocessor)
1. Pin Configuration
GRID KEY-OUT
Sit
G7 $12
G8 $13
$14
G10 $15
G11 (6) S16
G12 7) ViD4
Voo (8) vib2
CLK-7073 (9) RDS MODE
DATA-7073 (10) VOL DOWN
CH MODE @) uPD78044GF-152 VOL uP
aes
(2)
T
MUTE
ST-9216 413) Voo
CLOCK (14) =~ viD3
DATA @9) ST-4094
ST-7821 -———(6) ST-BY LED
RESET (7) Vss
$T-9701 48 RMC
Sis2299 a9) DB LINK
AVss 20 PWR DOWN
STEREO @1) DATA 7073
VIDS 22) KC/TOO
VID4 3) KuUTO1
RDS IN (24) K2/TO2
25{26)27)-+28)-29)-B0)-3 1)- 82-33-34) 85)-38)-G7)-38)-39) 40)
Pied
Beene
Rae We Ae ddd he deal
x= — to. “<> cr
See Beh See Ni | Mere Be ye
Sir? 2 fee eS ee Oe KEY-IN
i on Ss = z
pC ‘al :
£ 8 ; Up}

2. Pin Functions
Pin No. | Symbol Description RE
Logic
| 1-7 GRID 6-12 | Grid signal output for FIP. ae
; 8 VDD +5 V power supply.
9 CLK-7073 =| Clock port of LC7073.
10 DATA-7073 Data port of LC7073.
11 CH-MODE Control port for Dolby Pro-Logic Channel. H
12 ST-BY When the power is on, control data output is "H".
| When the power is off, control data output is "L"
| and last memory is actived.
13 ST-9216 Strobe port of TC-9216.
14 CLOCK | Clock output. =a
15..|. DATA | Data output.
16 | ST-7821 Strobe port of LC-7821.
17 RESET | Input for resetting CPU.
18 ST-9701 Strobe port of NJU-9701. |
t —{__—- ——4
19 ST-9299 | Strobe port of TC-9299A.
20 | AVss Ground
21 STEREO Input for detecting FM STEREO. H/M/L
22! VID5 | Control port of VCR2 front and rear.
23-554 VID4 Control port of VCD.
| 24 RDS IN Strobe port of TDA-7330B RDS input. L
25 | PROTECTION | Signal input for protection.
26 COC; TUNED Input for detecting the station during tuning. L
27 | STEP According to the region, input for selecting the frequency bands
and steps of FM and AM.
Settings are as follows.
REGION| FREQUENCE | STEP | PIN 27
| | | AMERICA|FM: 87.5 - 107.9 MHz} 200 KHz) 5V |
| AM: 520-1710 KHz | 10 KHz |
| EUROPE |FM: 87.5-108MHz | 50KHz| 2.5 V
L i 522-1611 KHz | 9 KHz| |
KOREA |FM: 87.5 - 107.5 MHz) 200 KHz} OV
| |AM: 522-1611 KHz | 9 KHz
28 |SIGNAL METER’ Input port of FM Signal. H/L
i 29 AVaag | Power supply of Analog A/D Converter. “a
| 30 AViet | Ref. Voltage of Analog A/D Converter. L
31 GND Ground.
| 32 N.C | Not used !
a Vss___ Ground.
34 X-TAL IN Input for crystal oscillator. |
35 X-TAL OUT | Output for crystal oscillator. z
36 C.MUTE ' Control port for Center Signal mute. H/L
37 S.MUTE Control port for Surround Signai mute. H/L
38 T/M MUTE Control port for Tape Monitor Signal mute.
39 M.MUTE Control port for Main Signal mute. H
10

; Active
Pin No. | D ipti
| No | Symbol escription | Logic
oT :
40 - 43 K3 - KO Data input for key scan. H
DATA - 7073 Data start of LC-7073.
45 PWR-DOWN Input for detecting power down. L
D-LINK Input/Output for controlling DIGI-LINK.
47 RMC input for remote control data. aay
Vss Ground.
ST-BY LED Output for driving stand-by LED. H
50 ST-4094 Strobe port of M-14094. H
51
52 [Vn | *5V power supply.
53
Output to drive volume motor for increasing volume level.
VOL.DOWN | Output to drive volume motor for decreasing volume level.
56 RDS MODE Control port for RDS mode.
mB
Ij
x
57 VID2 Control port for VCR2 hie.
58 viD1 Control port for VCR1.
59 - 70 SEG 16-5 Segment signal output for FIP.
71 Vioad -30 V power supply for FIP.
SEG 4-1 Segment signal output for FIP.
76
-
80
GRID
1-5
Grid
signal
output
for
FIP.
fe
3. Block Diagram
TOO/PI0 O=—] isbnTIMEN [A
TO1/P31 O 8 ba TIMER/ ==
Ti1/P33 0 EVENT COUNTER |
K > POO-PO4
TO2/P32
T12/P34
Bbit TIMERS
K—
sence [ef vom
/
WATCHDOG TIMER K —_ >
“WATCH TIMER
[rome F> mm
CIO/INTP3/PO3 oe Een ae f
COUNTER
coms om aa el 2 em E> vom
eee intenraceo K—Y
PORTIO [-_ > P100-P107
SCKO/P27
s1/P20 ©
s01/P21 ©
BeRL/P22
owe]
SERIAL
YA)
|
|
puzzer
[SOCK
|
crock
|
cock
cavmaror
|
sranp
By
INTERFACE 1 OUTPUT
stB/P23 © OUTPUT DIVIDER | sus | CONTROL
BUSY/P24
©
CONTROI.
Ko
PorTID.
«KC
pino-P17
O O
AYa, O
ANIO/P10. a,
a BUZ/P36 PCL/P35 PO4/XT1L XT2
AVps
O-—~-|A/D
CONVERTERK
—_
;
ate
Cy
rome
kD
P120-P127
oe ° | i | |
INTPO/TIO/POO
INTERRUPT
FIPO-FIP33
Lath
|
conmo.
K—~
FE
Mae
Se
vi
~INTP3/Cl0/PO3
O Vreso
11

4. Key Matrix
OUT| KSCANO!| KSCAN1 | KSCAN2/ KSCAN3/ KSCAN4| KSCANS5 | KSCAN6 | KSCAN7
IN PIN 61 PIN 62 PIN63 | PING4 | PINGS | PIN66 | PIN67 | PIN68
[ eS PUN
KEY INO | DISPLAY AM TAPE 1 | TAPE 2 CD 4 VCR2 > VCR1
PIN
43
|
{DCC
|
MON.
|
Fora ec ae eal rr
ONO
FM
4
2
DIRECT
A
Sia | (RDS PH | v
SS
STE
USE
SERRE
RE
eee
eee
KEYIN2|)
AF
CENTER
5
9
3
6
PIN
41
MODE
|
KEYIN3| DTY | SURROUND o | 8 7 MEMORY | AUTO FM
PIN 40 MODE | /IMANU | MODE
le
5. Digital Tuning System Description
<QquE FV PLL Loop
<7] AM PLL Loop
FM ANT ___FM FRONT END PACK
r — vee eens Ge ome ee om ee ee ag
FM RF FM MIX
FM OSC |
Keay
I
Low Pass Filter
Q902, Q903
ai
PLL Prescaler
FE 901
FM IN
1C901
AM IN
CCT Sr we Se we =
AM ANT
Data
CPU
1C201
AM OSC
Key
FL ;
[Butler | ! Display Switch
Matrix
!
I
I
|
!
|
1
i
|
1
I
1
|
!
i
i
L
12

« Vco vs. FM Band Frequency Curve
Po RE bel yop eto |
ge eT Te ee
EMER ES EERE RARER? AES
glibc Meaty tes Te foe te Ca We a ea A ge
sea eee ae Ae
ee Ae eee ee eee ee” eee
= pop fo fpf ttt AP
Bo og ae ee
Be eee ea ae oy eS
a nn nee cee eee eee
g tt et
Pe a i a Ha a AO
SERRE = «eee Ree eee
olde eer
pole Nee bole lael pad tear Paa EeD P hea
| 2 See
eee Sect cI A ae eal dea sled ed he peuple a ahs |
Pi eC a ee
875 895 915 935 95.5 975 99.5 101.5 103.5 105.5 107.5
FM Band Frequency(MHz)
¢ Vco vs. AM Band Frequency Curve
Ams.
NEE
SERER N
| | IN Pan |_|
Vco Voltage (V)
uo
SREP HSER RRR ER
Bana” de Se RaSh ARR
ha? Shh eae eee eee
ft ep tf
520 600 700 800 900 1000 1100 1200 1300 1400 1500 1600
4RR@ if Hae ee eaes
Sh RARER SR RARER
SERRE
ae
AM Band Frequency (kHz}
13

6. Level Diagram
Volume
Balance
Speaker
val cal Volume P
ff
Amp
O)
out
25.6V} 82W
80 8Q
70
28.8dB
60
50
ee 0.12dB 0.12V
35.5dB
0.028V
Audio Frequency (1kHz)
Voltage Gain in dB
14

7. Protection Circuits
¢ Speaker Protection Circuits
The CPU protects both this unit and the speakers when an abnormally high current fllows in Q309
L/R/C/S and 0310 L/R/C/S due to excessive input drive, too low of a load impedance, or short of the
speaker terminals.
If current increase is excessive the voltage across R316 L/R/C/S turns on 0312 L/R/C/S, then 0313 turns
and 0314. It makes the protection port of the CPU to low state, and the CPU turns off Q317 and Q316.
Then this unit goes to stand-by mode.
A Os, A 0312 Kd TO CENTER/REAR CHANNEL
Se
620
10/50
+12
fT)
' \ a
H = \ R337
‘ : eal TO SURROND 22K
: SPEAKER B'D
1
IN4148 & Ea
]
:
TO INPUT B'D 22K R339 TO CPU
22 Q314 | R338 (PROTECTION)
0314 K7\03198 33K
+ ‘ |
ole Ss
meta fi’ c3198
i % WR, / 0315
R331 R333
TO R CHANNEL
TO BIAS SUPPLY TO BIAS
Q317
2$D1302
15

« Thermal Protection Circuits
This receiver has a overload thermal protection circuits to guard against abnormal operation.
When the temperature of TRANS POSISTOR installed with the main transformer rises abnormally, the
resistance of the posistor becomes larger and 0314 is turned on.
It makes the protection port of the CPU to Low state, and the CPU turns off 0317 and 0313.
Then this unit goes to stand-by Mode.
22K
be Q314 TO CPU
R330 3198 R338 So (PROTECTION)
ise]
a) f- 0315 ° &
ak law b) C3198} 45
Sees ft-
C314 ote 8 1 )
= >
0.047(M) |
R336
3K
56)
CN106
[es
TRANS
POSISTOR
7.5K
R335 B.8V
D309
TO BIAS SUPPLY TO BIAS
TO CPU
(ST-BY)
Q317
2801302
16

ALIGNMENT PROCEDURES
Adjustment and Test Points (Tuner P.C. Board)
17

Before
adjustments,
refer
to
‘Adjustments
and
Test
Points"
on
Page
17.
Note:
As
a
front-end
(FE901)
is
difficult
to
repair
if
faulty,
replace
it
with
new
one.
FM SECTION
« Standard Setting of FM stereo RF Signal Generator.
STEREO STANDARD SIGNAL
Carrier frequency : 98.0 MHz
Modulation : Audio 1 kHz, 40 kHz deviafion.
Pilot 19 kHz, 7.5 kHz deviation
MONAURAL STANDARD SIGNAL
98.0 MHz
1 kHz, 45 kHz deviation
FM Discriminator Adjustment.
(NULL and MONO Distortion)
FM RF stereo signal Distortion
generator meter
Output level: ImV (50 dBu)
Antenna FM (7592) Tape 1
Won Output
{DC range)
(NULL)
TP2 =
TP3
Procedure :
1. Tune the set to 98.0 MHz.
2. Adjust L903 for 0 V reading on the VOM.
--NULL
3. Adjust L904 for a minimum reading on the
distortion meter. -+-+-+++-+++++- MONO Distortion
4.Repeat the adjustments of 2 and 3 several
times.
Note : When replacing the ceramic filter,
perform this alignment.
FM Stereo Distortion Adjustment
FM RF stereo signal Distortion
generator meter
6 dB Loss ——4 [7]
————_—_—_—_—o+
set “T_T
oo 2 +
ae
Antenna FM (75) = Tape 1
Output
Mode : stereo
Output level: 1 mV (60 dBu)
Procedure : :
1. Tune the set to 98.0 MHz.
Set SSG. output level to 1 mV (60 dBu)
2. Adjust IFT in FE 901 for a minimum reading on
the distortion meter.
18
FM Tuned Indication Lighting Level Adjustment
FM RFF stereo signal
generator
Output level : 7 uV (17 dBp)
Set FM Antenna teminal (75 $2)
Procedure :
1. Tune the set to 98.0 MHz.
Set SSG output level to 17 dBu.
2. Adjust VR 902 to the place where "TUNED"
indicator lights.

FM Stereo Separation Adjustment
FM PF stereo signal
generator
Mode : stereo
Output level : 1 mV (60 dBu)
Antenna FM (75 92) Tape 1
Output
Procedure :
FM stereo
signal generator
output channel!
VTVM VIVM
reading (dB)
connection
®
Adjust VR903
minimum reading.
R-CH. | R-CH. ©
©
L-CH. R-CH. | Adjust VR903 for
minimum reading.
L-CH. Stereo separation: © — ®
R-CH. Stereo separation: © - D
The separation of both channels should be
equal.
AM SECTION
AM RF
signal generator
I |
{ :
—_—_—_—P:
f 60cm |
| 26dBLoss ;
AM loop antenna
30% amplitude
modiulation by
400 Hz signal
Output Level : 80 dB(+26 dB Loss)
603 kHz, 999 kHz, 1404 kHz
AM loop antenna
AM antenna terminal
dBy/m = (SSG output level) - 26 dB
AM Vrt(Tunning Voltage) Adjustment
1. Set to AM 522 kHz and adjust L902 so that
voltage of TP1 becomes 1.1V +0.05V
2. Set to AM 1611 kHz and adjust TC902 so that
voltage of TP1 becomes 8.4 +0.05V
3. Repeat the above adjustments 1 and 2.
AM Tracking Adjustment
AM RF
signal generator
30% amplitude
modulation by
400 Hz signal
AM loop antenna
AM antenna terminal
dBu/m = (SSG output level) - 26 dB
1. Set to AM 603 kHz and adjust L901 to
maximize AUDIO output level.
2. Set to AM 1404 kHz and adjust TC901 to
maximize AUDIO output level.
3. Set to AM 999 kHz and adjust L905 to
maximize AUDIO output level.
4. Repeat the above adjustments 1, 2 and 3.
AM TUNED Level Adjustment
Procedure :
1. Set SSG output level so that antenna input
level of the set becomes 630 pV (56 dByu/m).
2. Adjust VR901 to the place where "TUNED"
indicator lights.

TROUBLESHOOTING
Symptom
Receiver inoperative
(FL indicator does not light)
Fuse blows when power is
turned on.
Power indicator lights but no sound
from both channels
Speaker A inoperative
Speaker B inoperative
One channel does not work when
volume is at maximum with a test
signal applied to the center terminal
of volume control VR5 of the dead
channel.
Speaker works normally but
headphones inopertive.
PHONO input inoperative
FM inoperative
Cause and Remedy
A) Faulty AC power cord.
Replace. °
B) Defect in the power switch.
Replace.
C) Broken wire in the power transformer.
Replace the power transformer.
D) Blown fuse.
Replace the fuse.
A) Defective power transformer.
Replace.
B) Short in the primary or secondary of the transformer
Circuitry.
Repair the short.
C) Damaged rectifier D361.
Replace the defective component(s).
D) Short circuit in the rectifier circuit.
Repair the short.
A) Speaker switch A or B defective.
Replace the defective switch(es).
B) Defect in transistor Q309 L/R, Q310 L/R on the Main
Board.
Replace the defective component(s).
A) Speaker switch A defective.
Replace.
A) Speaker switch B defective.
Replace.
A) Defect in transistor Q309 L/R, 0310 L/R on the Main
Board.
Locate and correct the defect.
B) Break in copper foil of printed circuit board.
Repair the short.
C) Short in speaker output terminal.
Repair or replace.
A) Headphone plug does not mate with jack.
Replace the plug.
B) Defective resistors R601 L/R.
Replace.
A) Poor contact in phono input jack.
Repair or replace the jack.
B) Defective phono switch or IC 106.
Replace.
A) Defective front-end. (FE407-G60)
Replace.
B) Defective FM switch
Replace the switch.
20

Symptom Cause and Remedy
FM inoperative C) Defective transistor Q902, 0904, 0908 L/R 0907, and
1C901, IC902.
Replace the defective transistor(s) or IC(s).
D) Defective coil L903 or L904
Replace the coil(s).
E) Defective lead-in.
Repair or replace the lead-in.
F) Ceramic filter CF1, CF2, defective.
Replace the defective ceramic filter(s).
G) Defective controller circuit component.
Replace.
Poor multiplex separation A) Improper adjustment.
Readjust VR903.
(Refer to stereo seperation adjustment)
B) IC903 defective.
Replace.
C) Variable resistor VR903.
Replace the variable resistor(s).
STEREO indicator does not light A) Defective indicator in FL.
Replace.
B) Improper adjustment of VR903 of tuner board.
Make readjustment.
C) Defective IC903
Replace the defective component.
FM volume not sufficient A) If volume from both L and R channels is not loud
enough :
Front-end Section defective
Faulty IC902, Coil L903.
If sound of one channel is not loud enough :
Defective L906 L/R
FM Mono has no effect A) Defective FM MODE switch.
Replace.
AM inoperative A) Damaged !C902 of tuner board.
Replace.
B) Defective L901, L902, L905 or CF4 of tuner board.
Replace the defective component(s).
C) Resistor R915, R916
Replace the defective component(s).
D) Capacitor C906, C926, C914 defective.
| Replace the defective capacitor(s).
i E) Defective AM switch.
Replace.
F) Defective varicap diode VD901.
Replace varicap diode(s).
G) Damaged AM loop antenna.
Repair or replace.
H) Defective controlier circuit component.
Replace.
Bass control has no effect A) Variable resistor VR201 defective.
Replace.
B) Defective R236L/R, R237L/R, C212L/R, C213L/R.
Replace the defective component(s).
21

Symptom
Treble control has no effect
Auto tune inoperative (UP/DOWN)
(AM or FM)
Memory setting(keys 1-10)
inoperative
FL inoperative
Noise Volume control
Remote Control Unit inoperative
E) In case of FM only, improper adjustment of FM
a ee
Manual tune inoperative( UP/DOWN)
Cc OO SSS
C) Defective 1C201(CPU Board) or IC1.
| Replace.
Cause and Remedy
A) Variable resistor VR202 defective.
B) Defective R238 L/R, R239 L/R, C214 L/R, C215 L/R
Replace the defective component(s).
A) Poor contact in UP/Down key.
Repair replace.
B) Defective 1C201
Replace.
C) Defective FL Display.
Replace.
D) Defective tuner circuit component.
Replace.
fron-end.
Replace.
A) Poor contact in Up/Down key.
Replace.
B) Defective IC201.
Replace.
A) Poor contact in memory keys 1-10.
Replace.
B) Poor contact in memory set key.
Replace.
C) Defective IC201.
Replace the defective component.
A) FL defective.
Replace.
B) Defective 1C201.
Replace.
C) Defective RESO201.
Replace.
A) Defective IC504
Replace.
B) Defective capacitor C574 or C575.
Replace the defective capacitor(s).
A) Weak Battery.
Replace.
B) Defective.
Replace.
22