WATSON VR-3780 User manual

SERVICE MANUAL
WATSON VR-3780
MODEL

1
TABLE OF CONTENTS
SAFETY&PRECAUTIONS................................................................................................ 2
EXTERNAL VIEWS......................................................................................................... 4
FRONT VIEWS FUNCTION.................................................................................................................... 4
REAR VIEWS FUNCTION...................................................................................................................... 6
ELECTRICAL ADJUSTMENT............................................................................................ 7
SPECIFICATIONS ......................................................................................................... 8
CIRCUIT INFORMATION............................................................................................... 9
INTERCONNECT WIRING DIAGRAM..................................................................................................... 9
POWER CIRCUIT DIAGRAM................................................................................................................. 10
POWER BLOCK DIAGRAM.................................................................................................................. 12
SYSCON CIRCUIT DIAGRAM............................................................................................................... 13
SERVO & SYSCON BLOCK DIAGRAM.................................................................................................. 15
A/V & SECAM COLOR CIRCUIT DIAGRAM........................................................................................... 16
VIDEO PLAYBACK/RECORD PATH FOR PAL.......................................................................................... 18
HIFI & SW CIRCUIT DIAGRAM.............................................................................................................. 19
PIF CIRCUIT DIAGRAM........................................................................................................................ 21
COMPONENTS LOCATION GUIDE ON PCB BOTTOM VIEW............................................ 23
PCB MAIN.......................................................................................................................................... 23
DISASSEMBLY ............................................................................................................. 24
PACKING ASS’Y .................................................................................................................................24
FRONT PANEL ASSEMBLY ................................................................................................................... 25
INSTRUMENT DISASSEMBLY ................................................................................................................. 29
ELECTRICAL PARTS LIST ............................................................................................... 30
PCB MAIN AS .................................................................................................................................... 30

2
SAFETY & PRECAUTIONS
SAFETY CHECK AFTER SERVING
Examine the area surrounding the repaired location for damage or deterioration. Observe that screw, parts and wires
havebeen returned to originalpositions.Afterwards, perform the followingtestsand conform the specifiedvaluesin order
to verify compliance whit safety standards.
1. Insulation resistance test
Confirm the specified insulation resistance between power cord plug prong and externally exposed parts of the set
(RF terminals, antenna terminals, video and audio input and output terminals, microphone jacks, earphone jacks, etc.)
is greater than values given in table 1 below.
2. Dielectric strengthen test
Confirm specified dielectric strengthen between power cord
plug prongs and exposed accessible parts of the set
(RF terminals, antenna terminals, video and audio input output
terminals, microphone jack, ear phone jacks, etc.)
is greater than values given table 1.
3. Clearance distance
When replacing primary circuit component, confirm specified clearance distance (d), (d ’ ) between soldered terminals,
and between terminals and surrounding metallic parts. See table below.
Rating for selected areas
* : Class model only
AC Line Voltage Region Insulation
Resistance Dielectric Strength Clearance Distance(d),(d)
100V Japan
> 1 MΩ /500V DC 1kV
AC 1min.
> 3
110 to 130V USA &
Canada -900V AC 1min.
> 3.2
* 110 to 130V
200 to 240V
Europe
Australia
Latin America
> 10 MΩ /500V DC 4kV AC 1min.
> 6(d)
> 8(d')
(a :Power cord)
This table is unofficial and for reference only. Be sure to confirm the precise values for your
particular country and locality
NOTE

3
SAFETY & PRECAUTIONS
4. Leakage current test
Confirm specified or lower leakage current between B(earth
ground, power cord plug prongs) and externally exposed accessi-
ble parts (RF terminals, antenna terminals, video and audio input
output terminals, microphone jacks, earphone jacks, etc.)
Measuring method:(Power ON) Insert load Z between B(earth
ground, power cord plug prongs) and exposed accessible parts.
Use on AC voltmeter to measure across both terminals of load Z.
See figure2 and following table.
Leakage current ratings for selected are as
AC Line Voltage Region Load Z Leakage Cur-
rent( i )Clearance Distance(d),(d’)
100V Japan 1k
Ω
i < 1 mArms Exposed accessible parts
110 to 130V USA &Canada
15kmF
1k Ω
i < 0.5mArms Exposed accessible parts
110 to 130V
200 to 240V Europe Australia 2k
Ω
i < 0.7mA peak
i < 2mAdc Antenna earth terminals
50k Ω
i < 0.7mA peak
i < 1mAdc Other terminals
This table is unofficial and for reference only. Be sure to confirm the precise values
for your particular country and locality.
NOTE

4
1. FRONT VIEWS FUNCTION
DVST7C3 FRONT VIEW
DVST7E3 FRONT VIEW
DVST7L3 FRONT VIEW
DVST7M3 FRONT VIEW
EXTERNAL VIEWS

5
DVST7J3 FRONT VIEW
DVST7D3 FRONT VIEW
DVST7B3 FRONT VIEW
DVST8T3 FRONT VIEW
DVST8W3 FRONT VIEW
POWER REWIND / REVIEW
STOP / EJECT FAST FORWARD / CUE
RECORD PLAY BACK
FRONT VIDEO/AUDIO INPUT JACK CHANNEL UP / DOWN
EXTERNAL VIEW

6
EXTERNAL VIEWS
2. REAR VIEWS FUNCTION
MONO 1 SCART TYPE REAR VIEW
MONO 2 SCART TYPE REAR VIEW
HI-FI 2 SCART TYPE REAR VIEW
MONO RCA TYPE REAR VIEW
HI-FI RCA TYPE REAR VIEW

7
ELECTRICAL ADJUSTMENT
1. PLAYBACK PHASE
ADJUSTMENT PROCEDURE
1. Play back the test tape. (DP-2)
2. Set the oscilloscope to the CHOP mode. Connect CH1 to the SW PULSE (PIN 4 of P502)
3. Connect CH2 to the ENVE signal (PIN5 of P502)
4. Insert PATH JIG and press "REC" button on the remote control.
5. Check the position of the V-sync from the rising edge of the SW pulse.
(Standard : 6.5H ± 0.5H)
ITEM MODE ADJUSTMENT
POINT CHECK POINT TEST EQUIPMENT TEST TAPE INPUT SIGNAL
6.5H
ADJUSTMENT PLAY [REC] BUTTON PIN 4 & PIN 5 OF P502 OSCILLOSCOPE DP-2 NO SIGNAL
ADJUSTMENT PARTS MEASURING POINT
PCB : MAIN - TOP VIEW
TMI
BLOC PRE-
AMP
P502
TO PATH JIG
OSCILLOSCOPE
CH1 CH2
PATH JIG

8
SPECIFICATIONS
CHANNEL COVERAGE
INPUT/OUTPUT JACK TYPE
GENERAL
Power Requirement
Power Consumption
Temperature
Operating position
Dimensions (W x H x D)
Weight
Format
Tape Width
Tape Speed
Maximum Recording Time with full-size cas-
sette
AC 230V, 50Hz
Max. 17W (in REC mode)
5 × C ~ 35 × C (Operating)
-20 × C ~ 60 × C
Horizontal only
360 x 90 x 288 (mm)
Approx. 3.85 Kg
VHS standard
12.65mm
(SP) : 23.39mm/sec
(LP) : 11.70mm/sec
(SP) :240min, with E-240 video cassette
(LP) :480min, with E-240 video cassette
VIDEO
Signal system
Recording system
Input
Output
Signal-to-Noise ratio
Horizontal resolution
PAL/SECAM colour and CCIR monochrome signals, 625 lines/50 fields
Rotary two-head helicalscan with a slantdouble-azimuth combination video
head
1.0Vp-p, 75ohms, unbalanced
1.0Vp-p, 75ohms, unbalanced
45dB (Rhode &Schwarz noise meter) with NETTETEIMAGE control at cen-
ter position
240 lines with NETTETE IMAGE control at center position
AUDIO
Recording system
Input
Output
Frequency Range
Signal to Noise Ratio
Audio Distortion
Longitudinal track
-8dBm, (CENELEC standard),more than 47 k-ohms, unbalanced
-6dBm, (CENELEC standard), less than 1k-ohms, unbalanced(100k-ohms,
load)
100Hz to 8,000Hz
More than 38dB
Less than 3% (SP)
TUNER
Tuning system
RF Output Voltage synthesized tuner Programmable V/S 99CH (Hyper band) UHF channel 21~69 (52)
TIMER
Memory programmable
Back up time
Clock exactness
99 CH
Less than 1 Hour
In accordance with the exactness of power supply frequency (50Hz)
ACCESSORIES
Provided Accessories Remote control unit, RF Cable, Battery
SYSTEM
SECAM-L
PAL, SECAM-B/G, PAL-I/I
PAL, SECAM-B/G, D/K, HYPER BAND PAL-I
CHANNEL
VHF Ch 2~12
UHF Ch 21~69
CATV Ch X,Y,Z S1~S41 UHF Ch 21~69
Model EUROPE Asia, South Africa, Australia
Jack Type SCART Type RCA Jack (Phone Jack)
* Design and specification can be subjected to change without notice.

9
CIRCUIT INFORMATION
1. INTERCONNECT WIRING DIAGRAM

10
CIRCUIT INFORMATION
2. POWER CIRCUIT DIAGRAM

11
CIRCUIT INFORMATION
POWER MODE
LOC. PIN EE PLAY REC.
IC802 12.46 2.46 2.46
24.81 4.83 4.82
3000.01
IC801 15.88 5.89 5.89
/803 24.81 4.83 4.83
30.25 0.25 0.25
43.1 3.1 3.1
POWER MODE
LOC. PIN EE PLAY REC.
Q801 E0 0 0
B-0.12 -0.11 -0.72
C323 323 323
Q802 E0 0 0
B0.25 0.26 0.17
C0.12 0.11 0.17
Q821 E12.58 12.6 12.6
B13.2 13.2 13.2
C15.6 15.36 15.4
Q822 E5.2 5.19 5.2
B5.89 5.89 5.89
C5.97 5.97 5.96
Q825 E0 0 0
B
C5.89 5.89 5.89
Q826 E0 0 0
B0.73 0.73 0.73
C
1. T801 PIN 1 X : 0.1KV DIV
Y : 5uS DIV
2. T801 PIN 3 X : 2V DIV
Y: 2mS DIV 3. T801 PIN4 X: 5V DIV Y: 5uS DIV
4.IC801 PIN3 X : 0.5V DIV
Y : 5uS DIV
5.IC801 PIN 4 X: 2VDIV
Y: 5uS DIV
6. Q801 base X: 0.5V DIV
Y : 5uS DIV

12
CIRCUIT INFORMATION
3. POWER BLOCK DIAGRAM

13
CIRCUIT INFORMATION
4. SYSCON CIRCUIT DIAGRAM

14
CIRCUIT INFORMATION
SYSCON MODE
LOC. PIN EE PLAY REC.
IC501 22.63 2.61 2.61
34.64 4.97 4.96
42.3 02.2
51.8 02.1
64.74 5.04 5.1
71.4 2.28 1.13
80.01 4.73 0.01
91.9 1.85 0.14
10 0.04 0.01 0.01
1
12 1.63 1.58 1.57
13 5.2 0.01 0.01
14 5.2 5.2 5.18
15 2.6 2.6 2.6
16 5.2 5.2 5.2
17 2.82 0 0
18 02.61 2.6
19 2.61 02.6
20 05.23 0
21 0 0 5.13
23 0.78 0.79 0.8
24 0.78 0.79 0.8
25 0.87 0.01 0.87
26 0.87 0.87 0.87
27 0.87 0.87 0.87
28 0.87 0.87 0.87
29 0.87 0.87 0.87
30 0.87 0.87 0.01
31 1.41 0.03 1.4
32 5.05 0.05 0.07
33 0.76 0.02 0.77
34 5.25 5.25 5.23
35 000
36 1.54 1.52 1.53
37 5.2 5.25 5.1
38 2.32 2.32 2.31
39 00.01 2.6
40 00.01 0.11
41 0 0 0.12
42 5.23 5.23 5.1
43 5.25 5.23 5.23
44 1.8 1.9 1.7
45 5 5 4.9
46 0.01 00.12
47 1.8 1.86 1.7
48 0.01 00.12
49 0.02 0 0
50 1.9 1.97 1.7
51 3.3 3.3 3.2
52 1.9 1.97 2.1
53 5.25 5.25 5.25
54 2.23 2.23 2.23
55 1.92 1.97 1.75
56 1.9 1.98 1.87
58 4.48 0.33 4.49
59 5.21 5.21 0
60 4.82 4.8 4.84
61 4.96 4.8 4.91
SYSCON MODE
LOC. PIN EE PLAY REC.
62 0.01 0.03 0
63
64 5.18 05.18
65 5.18 0.01 5.18
66 0.04 0.01 0.12
67 0 5.2 0
68 0 0.01 0
69 0 0 0.12
70 5.17 5.17 5.15
71 5.04 5.01 5.01
72 5.01 5.01 5.01
73 0.12 0.14 0.08
74 0.3 2.58 0.09
75 0.03 00.09
76 0 2.5 2.57
77 0 2.6 2.72
78 1.33 00.09
79 0 0 5 05
80 5.02 0 5 05
81 1.6 0.01 1.58
82 5.21 0 0
83 4.55 5.01 5.01
84 5.01 5.01 5.19
85 0.01 0.01 0
86 5.21 0.01 0
87 4.23 2.49 2.48
88 0 0.01 0
89 0 0.01 1.51
90 0.01 1.28 1.28
91 2.58 2.58 2.58
92 2.6 2.6 2.6
93
94 2.6 2.6 2.28
95 2.56 2.56 2.89
96 2.56 2.56 2.56
97 2.57 2.59 2.57
98 5.01 5.01 5.01
99 5.22 5.21 5.2
100 00.01 0
SYSCON MODE
LOC. PIN EE PLAY REC.
IC502
54.96 4.85 4.9
64.96 4.88 4.9
85.22 5.22 5.2
SYSCON MODE
LOC. PIN EE PLAY REC.
Q501 E2.82 3.06 2.81
B2.12 2.35 2.11
C0.01 0.01 0.02
<->
<-> <->
<->
1. IC501 PIN97 X: 1V DIV
CTL AMP OUT Y : 5mS DIV 2. IC501 PIN 89 X : 0.5V DIV DRUM FG Y :0.5ms DIV 3. IC501 PIN 87 X: 1V DIV CAPSTANFG Y:0.5mS DIV
4. IC501 PIN 77 X : 1V DIV
CAPSTAN PWM Y : 5uS DIV
5. IC501 PIN61 X: 1V DIV
SERIAL CLK Y: 0.1mS DIV
6. IC501 PIN60 X : 1V DIV
SERIAL DATA Y : 0.1mS DIV
7. IC501 PIN 56 X : 0.5V DIV
EDS IN Y: 20uS DIV

15
CIRCUIT INFORMATION
5. SERVO & SYSCON BLOCK DIAGRAM

16
CIRCUIT INFORMATION
6. AV & SECAM COLOR CIRCUIT DIAGRAM

17
CIRCUIT INFORMATION
A/V MODE
LOC. PIN EE PLAY REC.
IC301 15.09 0.1 0.78
20.03 0.03 0.84
32.29 2.28 2.55
40.33 0.17 0.62
52.28 2.27 2.49
62.29 2.28 2.27
72.28 2.28 2.28
82.28 2.28 2.28
92.28 2.28 2.25
10 2.29 2.28 2.28
11 2.4 2.4 2.4
12 0.02 0.02 0.02
13 2.29 2.28 2.27
14 0.05 0.04 0.04
15 2.29 2.28 2.27
16 5.16 0.18 5.15
17 2.29 2.28 2.27
18 5.15 5.121 5.14
19 4.21 4.16 4.13
20 0.02 0.02 0.02
21 3.32 1.99 3.32
22 3.2 3.17 3.2
23 3.2 3.2 3.2
24 5.16 5.13 5.16
25 0.16 3.3 0.15
26 1.42 1.67 1.42
27 2.1 2.1 2.04
28 4.2 4.16 4.17
29 2.79 2.74 2.81
30 0.02 00.02
32 5.07 4.91 4.97
33 2.12 2.03 2.11
34 1.57 1.57 1.57
35 2.1 2.09 2.1
36 3.48 3.45 3.59
37 1.69 1.66 1.72
38 2.04 2.01 2.08
39 9.5 9.47 9.48
40 0.02 0.02 0.02
41 0.02 0.02 0.02
42 5.16 5.13 5.15
43 2.23 2.44 2.23
44 0.06 4.21 0.04
45 2.27 2.28 2.29
46 2.42 2.67 2.43
47 4.15 4.15 4.16
48 1.89 1.89 1.88
49 2.94 3.16 2.94
50 1.95 1.95 1.93
51 0.02 0.02 0.02
52 1.94 1.95 1.92
53 1.35 2.34 2.18
54 1.94 1.95 1.92
55 5.17 5.17 5.14
56 2.17 2.31 2.16
57 22.15 2
58 1.98 1.98 1.98
59 2.93 2.95 2.92
60 1.43 1.58 1.43
61 1.57 1.86 1.58
62 00.07 0.07
A/V MODE
LOC. PIN EE PLAY REC.
63 1.19 1.02 1.21
64 0.02 0.02 0.02
65 0.85 1.92 0.86
66 0.06 1.45 0.07
67 4.49 0.35 4.49
68 5.05 5.07 5.05
69 5 5.01 5.01
70 0.01 2.61 2.6
71 1.73 1.68 1.67
72 5.12 5.1 5.11
73 2.2 2.06 2.2
74 2.3 2.6 2.31
75 2.22 0.69 2.23
76 2.22 0.76 2.23
77 1.7 1.52 1.6
78 2.66 3.37 2.67
79 2.02 1.96 2.52
80 0.95 0.96 4.53
81 1.15 1.14 1.15
82 0.02 0.02 0.02
83 0.45 1.35 1.28
84 1.39 2.26 1.13
85 0.39 0.02 0.66
86 0.2 0.27 1.63
87 1.93 1.96 4.35
88 1.93 1.95 4.33
89 1.93 1.95 4.33
90 1.93 1.96 4.35
91 5.14 5.12 5.12
92 0.02 0.02 0.02
93 1.94 0.74 0.73
94 1.94 0.74 0.73
95 1.94 0.74 0.73
96 1.95 0.74 0.73
97 0 0.02 0.02
98 2.29 2.29 2.43
99 2.29 2.29 2.43
100 2.29 2.29 2.56
A/V MODE
LOC. PIN EE PLAY REC.
Q201 E0.02 0.02 0.02
B0.03 0.03 0.84
C5.11 0.1 0.77
Q203 E3.51 0.1 0.89
B3.43 0.04 1.64
C5.04 0.04 4.83
Q204 E00.02 -14.24
B00.7 -19.43
C5.11 0.03 1.05
Q205 E0.14 0.02 -14.15
B00.71 -18.87
C0.02 0.02 0.02
Q206 E5.16 5.16 5.16
B5.16 4.46 5.15
C1.81 5.12 -19.1
Q207 E5.97 5.97 5.91
B5.96 5.96 5.11
C5.34 0.02 5.07
Q208 E000
B000.68
C5.96 5.96 0.02
Q301 E2.14 2.13 2.15
B2.78 2.76 2.76
C5.16 5.15 5.15
Q305 E1.4 1.32 1.4
B2.03 2.3 2.06
C5.17 5.17 5.16
Q330 E2.73 2.01 2.73
B2.05 2.67 2.05
C00.12 0
Q331 E2.06 2.32 2.06
B2.73 2.98 2.72
C5.17 5.17 5.16
SECAM COLOR MODE
LOC. PIN EE PLAY REC.
IC361 12.58 2.58 2.55
22.39 2.4 2.4
33.6 3.59 3.63
42.67 2.66 2.64
50.02 00.01
60.38 3.72 0.49
70.02 0.02 0.03
80.02 0.02 0.03
93.13 3.13 3.12
10 4.83 4.83 4.79
11 1.96 1.95 2
12 2.2 1.99 2.28
13 3.98 3.98 3.99
14 2.61 2.61 2.58
15 3.1 2.6 3.13
16 3.18 3.18 3.19
17 05.23 0
18 0.14 2.1 0.15
19 2.27 2.27 2.3
20 1.9 2.95 1.93
21 2.04 2.32 2.03
22 0.9 00.01
23 5.15 5.14 5.13
24 5.15 5.14 5.13
25 2.26 2.21 2.27
26 2.26 2.21 2.24
27 4.85 4.9 4.84
28 4.66 4.65 4.64
29 0.39 0.35 0.39
30 1.83 1.83 1.83
1. IC301 PIN78 X: 0.1V DIV
RECY-FM Y : 10uS DIV
2. IC301 PIN21 X: 0.1V DIV
REC COLOR(PAL) Y:20uS DIV
5. IC301 PIN21 X: 0.1V DIV
PB COLOR(SCM) Y : 20uS DIV
8. IC301 PIN50 X: 0.2V DIV
VIDEO INPUT(REC) Y : 20uS DIV
3. IC301 PIN25 X: 0.1V DIV
PB COLOR(PAL) Y: 20uS DIV
4. IC301 PIN25 X: 0.1V DIV
REC COLOR (SCM)Y :20uS DIV
6. IC301 PIN3 X : 1V DIV
C.SYNC Y : 20uS DIV
7. IC301 PIN58 X: 0.2V DIV
REC SECAM Y: 20uS DIV
9. IC301 PIN79 X : 0.1V DIV
PB ENVE Y : 2mS DIV 10. IC301 PIN43 X : 0.1V DIV Y-DLY OUT(PB) Y 20uS DIV
11. IC301 PIN43 X: 0.1V DIV
Y-DLY OUT(REC) Y : 20us DIV 12. IC301 PIN74 X: 0.1V DIV DEEMPHAOUT (PB) Y:20uS DIV 13. IC301 PIN65 X: 0.5V DIV VIDEO OUT(REC) Y : 20uS DIV

18
CIRCUIT INFORMATION
7-1. VIDEO PLAYBACK PATH FOR PAL
7-2. VIDEO RECORD PATH FOR PAL

19
CIRCUIT INFORMATION
8. HIFI & SW CIRCUIT DIAGRAM