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SERVICE MANUAL
No. 82792
March 2000
HR-S3800U/S4800U
SPECIFICATIONS
VIDEO CASSETTE RECORDER
This service manual is made from all recycled paper.
COPYRIGHT © 2000 VICTOR COMPANY OF JAPAN, LTD.
TV CH +
T
V
V
O
L
­
TV CH ­
TV
V
O
L
+
TV
CANCEL
TIMER
START
STOP
DATE
PLAY
REW
REC
STOP
SHUTTLE
PLUS
PAUSE
FF
MEN
U
OK
CH
POWER
TV/VCR
C.RESET
DBS
DAILY(M-F)
AUX
WEEKLY
PROG
CHECK
PROG
SP/EP
SKIP SEARCH
DISPLAY
A. MONITOR
CABLE/
DBS
123
45
6
7
89
0
2
4
1
3
EXPRESS PROGRAMMING
MULTI BRAND
REMOTE CONTROL UNIT
MBR SET
A/B
VIDEO (MONO)L--AUDIO--R
S-VIDEO
MENU
OK
CH
S-VHS ET
FF
REW
POWER
SP
EP
VCR
REC
PAUSE
STOP/EJECT
PLAY
GENERAL
Power requirement
: AC 120 V`, 60 Hz
Power consumption
Power on
: 20 W
Power off
: 2.5 W
Temperature
Operating
: 5°C to 40°C (41°F to 104°F)
Storage
: ­20°C to 60°C (­4°F to140°F)
Operating position
: Horizontal only
Dimensions (W x H x D) : 400 x 94 x 281 mm
(15-3/4" x 3-3/4" x 11-1/8")
Weight
: 3.4 kg (7.5 lbs)
Format
: S-VHS/VHS NTSC standard
Maximum recording time
SP
: 210 min. with ST-210 video cassette
EP
: 630 min. with ST-210 video cassette
VIDEO/AUDIO
Signal system
: NTSC-type color signal and EIA
monochrome signal, 525 lines/60
fields
Recording/Playback
system
: DA-4 (Double Azimuth) head
helical scan system
Signal-to-noise ratio
: 45 dB
Horizontal resolution
VHS
: 230 lines
S-VHS
: 400 lines
Frequency range
Normal audio
: 70 Hz to 10,000 Hz
Hi-Fi audio
: 20 Hz to 20,000 Hz
Input/Output
: RCA connectors (IN x 2, OUT x 1)
S-video connectors (IN x 2, OUT x 1)
TUNER
Tuning system
: Frequency-synthesized tuner
Channel coverage
VHF
: Channels 2­13
UHF
: Channels 14­69
CATV
: 113 Channels
RF output
: Channel 3 or 4 (switchable;
preset to Channel 3 when
shipped) 75 ohms, unbalanced
TIMER
Clock reference
: Quartz
Program capacity
: 1-year programmable timer/8 programs
Memory backup time
: Approx. 3 min.
ACCESSORIES
Provided accessories
FOR HR-S4800U : Infrared remote control unit,
"AA" battery x 2,
Audio/video cable,
S-video cable (4-pin),
S-VHS ET labels,
Controller
FOR HR-S3800U : Infrared remote control unit,
"AA" battery x 2,
Audio/video cable,
S-video cable (4-pin),
S-VHS ET labels,
Specifications shown are for SP mode unless specified otherwise.
E. & O.E. Design and specifications subject to change without notice.


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3.1.1 Required test equipments .............................................. 3-1
3.1.2 Required adjustment tools ............................................. 3-1
3.1.3 Color (colour) bar signal,Color (colour) bar pattern .......... 3-1
3.1.4 Switch settings and standard precautions ...................... 3-1
3.1.5 EVR Adjustment .............................................................. 3-2
3.2 SERVO CIRCUIT ................................................................... 3-2
3.2.1 Switching point ................................................................ 3-2
3.2.2 Slow tracking preset ........................................................ 3-2
3.3 VIDEO CIRCUIT .................................................................... 3-3
3.3.1 D/A level .......................................................................... 3-3
3.3.2 EE Y level ........................................................................ 3-3
3.3.3 REC color (colour) level ................................................... 3-3
3.3.4 PB Y level (S-VHS/VHS) ................................................... 3-4
3.3.5 Video EQ (Frequency response) ...................................... 3-4
3.3.6 AUTO PICTURE initial setting .......................................... 3-4
3.4 AUDIO CIRCUIT ................................................................... 3-5
3.4.1 Audio REC FM ................................................................. 3-5
3.5 DEMODULATOR CIRCUIT ................................................... 3-5
3.5.1 Input level ........................................................................ 3-5
3.5.2 Stereo VCO ..................................................................... 3-5
3.5.3 Stereo filter ...................................................................... 3-6
3.5.4 Separation - 1 .................................................................. 3-6
3.5.5 Separation - 2 .................................................................. 3-6
3.5.6 SAP VCO ......................................................................... 3-6
4. CHARTS AND DIAGRAMS
NOTES OF SCHEMATIC DIAGRAM ............................................ 4-1
CIRCUIT BOARD NOTES ............................................................. 4-2
4.1 BOARD INTERCONNECTIONS ............................................ 4-3
4.2 VIDEO/AUDIO SCHEMATIC DIAGRAM ............................... 4-5
4.3 SYSTEM CONTROL SCHEMATIC DIAGRAM ...................... 4-7
4.4 SWITCHING REGULATOR SCHEMATIC DIAGRAM ............ 4-9
4.5 TUNER SCHEMATIC DIAGRAM ........................................ 4-11
4.6 DISPLAY, S JACK AND SHUTTLE SCHEMATIC DIAGRAMS .. 4-13
4.7 TERMINAL SCHEMATIC DIAGRAM .................................. 4-15
4.8 BS CONNECTION, C.BOX AND R.PAUSE SCHEMATIC
DIAGRAMS ........................................................................ 4-16
4.9 S-SUB AND SUB EMPHA SCHEMATIC DIAGRAMS ......... 4-17
4.10 2D DIGITAL SCHEMATIC DIAGRAM ............................... 4-19
4.11 DEMODULATOR SCHEMATIC DIAGRAM ...................... 4-21
4.12 MAIN, A/C HEAD, C.BOX, S JACK, R.PAUSE, SHUTTLE
AND LOADING MOTOR CIRCUIT BOARDS ................... 4-25
4.13 2D DIGITAL CIRCUIT BOARD ......................................... 4-28
4.14 SUB EMPHA CIRCUIT BOARD ....................................... 4-29
4.15 DEMODULATOR CIRCUIT BOARD ................................. 4-30
4.16 FDP GRID ASSIGNMENT AND ANODE CONNECTION .. 4-31
4.17 REMOTE CONTROL SCHEMATIC DIAGRAM ................. 4-32
4.18 VOLTAGE CHARTS .......................................................... 4-33
4.19 SYSTEM CONTROL BLOCK DIAGRAM .......................... 4-37
4.20 VIDEO BLOCK DIAGRAM ............................................... 4-39
4.21 AUDIO BLOCK DIAGRAM ............................................... 4-43
5. PARTS LIST
5.1 PACKING AND ACCESSORY ASSEMBLY <M1> ................ 5-1
5.2 CABINET AND CHASSIS ASSEMBLY <M2> ...................... 5-2
5.3 MECHANISM ASSEMBLY <M4> ....................................... 5-4
5.4 ELECTRICAL PARTS LIST .................................................... 5-6
MAIN BOARD ASSEMBLY <03> .............................................. 5-6
2D DIGITAL BOARD ASSEMBLY <05> .................................. 5-12
R.PAUSE BOARD ASSEMBLY <06> ....................................... 5-13
SUB EMPHA BOARD ASSEMBLY <08> ................................. 5-13
AUDIO CONTROL HEAD BOARD ASSEMBLY <12> ............. 5-13
DEMOD BOARD ASSEMBLY <14> ........................................ 5-13
S JACK BOARD ASSEMBLY(S4800U/U(C)) <36> ................... 5-14
LOADING MOTOR BOARD ASSEMBLY <55> ....................... 5-14
SHUTTLE BOARD ASSEMBLY <85> ...................................... 5-14
C.BOX BOARD ASSEMBLY <92> ........................................... 5-14
Important Safety Precautions
INSTRUCTIONS
1. DISASSEMBLY
1.1 DISASSEMBLY FLOW CHART ............................................. 1-1
1.2 HOW TO READ THE DISASSEMBLY AND ASSEMBLY ...... 1-1
1.3 DISASSEMBLY/ASSEMBLY METHOD ................................. 1-1
1.4 SERVICE POSITION ............................................................. 1-4
1.4.1 How to take out the Mechanism and Main board assemblies 1-4
1.5 MECHANISM SERVICE MODE ............................................ 1-5
1.5.1 How to set the "MECHANISM SERVICE MODE" ............ 1-5
1.6 EMERGENCY DISPLAY FUNCTION ....................................... 1-6
1.6.1 Displaying the emergency information ............................ 1-6
1.6.2 Clearing the emergency history ...................................... 1-6
1.6.3 Emergency content description ...................................... 1-7
1.6.4 Emergency detail information 1 ..................................... 1-8
1.6.5 Emergency detail information 2 ..................................... 1-9
1.7 SYSCON CIRCUIT .............................................................. 1-10
1.7.1 Syscon CPU pin function (IC3001) ................................ 1-10
2. MECHANISM ADJUSTMENT
2.1 BEFORE STARTING REPAIR AND ADJUSTMENT ................ 2-1
2.1.1 Precautions ...................................................................... 2-1
2.1.2 Checking for Proper Mechanical Operations ................... 2-1
2.1.3 Manually Removing the Cassette Tape ........................... 2-1
2.1.4 Jigs and Tools Required for Adjustment .......................... 2-3
2.1.5 Maintenance and Inspection ........................................... 2-3
2.2 REPLACEMENT OF MAJOR PARTS .................................... 2-6
2.2.1 Before Starting Disassembling (Phase matching
between mechanical parts) ............................................. 2-6
2.2.2 How to Set the Mechanism Assembling Mode .............. 2-7
2.2.3 Cassette Holder Assembly .............................................. 2-7
2.2.4 Pinch Roller Arm Assembly ........................................... 2-10
2.2.5 Guide Arm Assembly and Press Lever Assembly ......... 2-10
2.2.6 Audio Control Head ....................................................... 2-10
2.2.7 Loading Motor ............................................................... 2-11
2.2.8 Capstan Motor ............................................................... 2-11
2.2.9 Pole Base Assembly (supply or take-up side) ................ 2-12
2.2.10 Rotary Encoder ........................................................... 2-12
2.2.11 Clutch Unit .................................................................. 2-13
2.2.12 Change Lever Assembly, Direct Gear and Clutch Gear1 . 2-13
2.2.13 Link Lever ................................................................... 2-13
2.2.14 Cassette Gear, Control Cam and Worm Gear ............. 2-14
2.2.15 Control Plate ............................................................... 2-14
2.2.16 Loading Arm Gear (supply or take-up side) and
Loading Arm Gear Shaft ............................................. 2-15
2.2.17 Take-up Lever, Take-up Head and Control Plate Guide 2-16
2.2.18 Capstan Brake Assembly ............................................ 2-16
2.2.19 Sub Brake Assembly (take-up side) ............................ 2-17
2.2.20 Main Brake Assembly (take-up side), Reel Disk (take-up
side) and Main Brake Assembly (supply side) .................. 2-17
2.2.21 Tension Brake Assembly, Reel Disk (supply side) and
Tension Arm Assembly ............................................... 2-17
2.2.22 Idler Lever, Idler Arm Assembly ................................. 2-18
2.2.23 Stator Assembly ......................................................... 2-18
2.2.24 Rotor Assembly .......................................................... 2-18
2.2.25 Upper Drum Assembly ............................................... 2-19
2.3 COMPATIBILITY ADJUSTMENT ........................................ 2-20
2.3.1 Checking/Adjustment of FM Waveform Linearity ......... 2-20
2.3.2 Checking/Adjustment of the Height and Tilt of the
Audio Control Head ....................................................... 2-21
2.3.3 Checking/Adjustment of the Audio Control Head Phase (X-Value) . 2-21
2.3.4 Checking/Adjustment of the Standard Tracking Preset . 2-22
2.3.5 Checking/Adjustment of the Tension Pole Position ....... 2-22
3. ELECTRICAL ADJUSTMENT
3.1 PRECAUTION ...................................................................... 3-1
HR-S3800U/U(C)
HR-S4800U/U(C)
FLYING ERASE HEAD
NOT USED
USED
INSERT EDIT
NOT USED
USED
AUDIO DUBBING
NOT USED
USED
FRONT S-VIDEO INPUT TERMINAL
NOT USED
USED
CABLE MOUSE
OPTION
PROVIDEO
The following table lists the differing points between Models ( HR-S3800U/U(C) and HR-S4800U(C) ) in this series.
TABLE OF CONTENTS
Section
Title
Page
Section
Title
Page


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Important Safety Precautions
Prior to shipment from the factory, JVC products are strictly inspected to conform with the recognized product safety and electrical codes
of the countries in which they are to be sold. However, in order to maintain such compliance, it is equally important to implement the
following precautions when a set is being serviced.
Fig.1
1. Locations requiring special caution are denoted by labels and
inscriptions on the cabinet, chassis and certain parts of the
product. When performing service, be sure to read and com-
ply with these and other cautionary notices appearing in the
operation and service manuals.
2. Parts identified by the
symbol and shaded (
) parts are
critical for safety.
Replace only with specified part numbers.
Note: Parts in this category also include those specified to com-
ply with X-ray emission standards for products using
cathode ray tubes and those specified for compliance
with various regulations regarding spurious radiation
emission.
3. Fuse replacement caution notice.
Caution for continued protection against fire hazard.
Replace only with same type and rated fuse(s) as specified.
4. Use specified internal wiring. Note especially:
1) Wires covered with PVC tubing
2) Double insulated wires
3) High voltage leads
5. Use specified insulating materials for hazardous live parts.
Note especially:
1) Insulation Tape
3) Spacers
5) Barrier
2) PVC tubing
4) Insulation sheets for transistors
6. When replacing AC primary side components (transformers,
power cords, noise blocking capacitors, etc.) wrap ends of
wires securely about the terminals before soldering.
Power cord
Fig.2
10. Also check areas surrounding repaired locations.
11. Products using cathode ray tubes (CRTs)
In regard to such products, the cathode ray tubes themselves,
the high voltage circuits, and related circuits are specified for
compliance with recognized codes pertaining to X-ray emission.
Consequently, when servicing these products, replace the cath-
ode ray tubes and other parts with only the specified parts.
Under no circumstances attempt to modify these circuits.
Unauthorized modification can increase the high voltage value
and cause X-ray emission from the cathode ray tube.
12. Crimp type wire connector
In such cases as when replacing the power transformer in sets
where the connections between the power cord and power
transformer primary lead wires are performed using crimp type
connectors, if replacing the connectors is unavoidable, in or-
der to prevent safety hazards, perform carefully and precisely
according to the following steps.
1) Connector part number : E03830-001
2) Required tool : Connector crimping tool of the proper type
which will not damage insulated parts.
3) Replacement procedure
(1) Remove the old connector by cutting the wires at a point
close to the connector.
Important : Do not reuse a connector (discard it).
Fig.7
cut close to connector
Fig.3
(2) Strip about 15 mm of the insulation from the ends of
the wires. If the wires are stranded, twist the strands to
avoid frayed conductors.
15 mm
Fig.4
(3) Align the lengths of the wires to be connected. Insert
the wires fully into the connector.
Connector
Metal sleeve
Fig.5
(4) As shown in Fig.6, use the crimping tool to crimp the
metal sleeve at the center position. Be sure to crimp fully
to the complete closure of the tool.
1
Precautions during Servicing
7. Observe that wires do not contact heat producing parts
(heatsinks, oxide metal film resistors, fusible resistors, etc.)
8. Check that replaced wires do not contact sharp edged or
pointed parts.
9. When a power cord has been replaced, check that 10-15 kg of
force in any direction will not loosen it.
1.25
2.0
5.5
Crimping tool
Fig.6
(5) Check the four points noted in Fig.7.
Not easily pulled free
Crimped at approx. center
of metal sleeve
Conductors extended
Wire insulation recessed
more than 4 mm
S40888-01


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Safety Check after Servicing
Examine the area surrounding the repaired location for damage or deterioration. Observe that screws, parts and wires have been
returned to original positions, Afterwards, perform the following tests and confirm the specified values in order to verify compli-
ance with safety standards.
1. Insulation resistance test
Confirm the specified insulation resistance or greater between power cord plug prongs and
externally exposed parts of the set (RF terminals, antenna terminals, video and audio input
and output terminals, microphone jacks, earphone jacks, etc.). See table 1 below.
2. Dielectric strength test
Confirm specified dielectric strength or greater between power cord plug prongs and exposed
accessible parts of the set (RF terminals, antenna terminals, video and audio input and output
terminals, microphone jacks, earphone jacks, etc.). See table 1 below.
3. Clearance distance
When replacing primary circuit components, confirm specified clearance distance (d), (d') be-
tween soldered terminals, and between terminals and surrounding metallic parts. See table 1
below.
4. Leakage current test
Confirm specified or lower leakage current between earth ground/power cord plug prongs
and externally exposed accessible parts (RF terminals, antenna terminals, video and audio
input and output terminals, microphone jacks, earphone jacks, etc.).
Measuring Method : (Power ON)
Insert load Z between earth ground/power cord plug prongs and externally exposed accessi-
ble parts. Use an AC voltmeter to measure across both terminals of load Z. See figure 9 and
following table 2.
5. Grounding (Class 1 model only)
Confirm specified or lower grounding impedance between earth pin in AC inlet and externally exposed accessible parts (Video in,
Video out, Audio in, Audio out or Fixing screw etc.).
Measuring Method:
Connect milli ohm meter between earth pin in AC inlet and exposed accessible parts. See figure 10 and grounding specifications.
Fig. 10
Fig. 9
Fig. 8
Table 1 Specifications for each region
Table 2 Leakage current specifications for each region
Note: These tables are unofficial and for reference only. Be sure to confirm the precise values for your particular country and locality.
2
S40888-01
d'
d
Chassis
Power cord,
primary wire
ab
c
V
A
Externally
exposed
accessible part
Z
Region
USA & Canada
Europe & Australia
Grounding Impedance (Z)
Z
0.1 ohm
Z
0.5 ohm
AC inlet
Earth pin
Exposed accessible part
Milli ohm meter
Grounding Specifications
Clearance Distance (d), (d')
d, d'
3 mm
d, d'
4 mm
d, d'
3.2 mm
1 M
R 12 M/500 V DC
Dielectric Strength
AC 1 kV 1 minute
AC 1.5 kV 1 miute
AC 1 kV 1 minute
AC Line Voltage
100 V
100 to 240 V
110 to 130 V
110 to 130 V
200 to 240 V
Japan
USA & Canada
Europe & Australia
R
10 M
/500 V DC
Region
Insulation Resistance (R)
R
1 M
/500 V DC
AC 3 kV 1 minute
(Class
2)
AC 1.5 kV 1 minute
(Class
1)
d
4 mm
d'
8 mm (Power cord)
d'
6 mm (Primary wire)
a, b, c
Leakage Current (i)
AC Line Voltage
100 V
110 to 130 V
110 to 130 V
220 to 240 V
Japan
USA & Canada
i
1 mA rms
Exposed accessible parts
Exposed accessible parts
Antenna earth terminals
Other terminals
i
0.5 mA rms
i
0.7 mA peak
i
2 mA dc
i
0.7 mA peak
i
2 mA dc
Europe & Australia
Region
Load Z
1 k
2 k
1.5 k
0.15
µF
50 k


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1-2
Fig. D2
Fig. D4
Fig. D1
Fig. D3
(S1)
1
(S1)
(S1)
(S2)
(L3)
(L3)
<NOTE 3a>
WR3a
<NOTE 3b>
(L3)
CN7001
FOIL SIDE
<NOTE 3c>
CN7108
(S3)
S JACK
board assembly
WR3b
SUPPORTING
TAPE SIDE
<NOTE 3c>
FRONT PANEL
BACK SIDE
(S4a)
WR4b
WR4a
4
CN1
a
c
CN1
b
FOIL SIDE
<NOTE 3c>
FOIL SIDE
<NOTE 3c>
DRUM SHIELD
(S4b)
(S4a)
(L4a)
(L4b)
(P4)
ROLLER ARM
ASSEMBLY
INERTIA PLATE
NOTE: When installing the DRUM assembly, secure the
screws (S4a) in the order of a , b , c .