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SERVICE MANUAL
No. 82847
January 2001
SPECIFICATIONS (The specifications shown pertain specifically to the model HR-J785EK)
VIDEO CASSETTE RECORDER
Printed in Japan
VICTOR COMPANY OF JAPAN, LIMITED
VIDEO DIVISION
S40894
This service manual is printed on 100% recycled paper.
COPYRIGHT © 2001 VICTOR COMPANY OF JAPAN, LTD.
HR-J680EK/EU,
J780EU,
J785EK
No.
82847
PAL
TV PR +
TV PR ­
T
V
­
TV
+
TV
0000
STOP
FIN
MEN
U
OK
TV/VCR
DAILY/QTDN.
VPS/PDC
AUX
?
WEEKLY/HEBDO
PROG
30 SEC
­ ­:­ ­
AUDIO
12
3
4
6
5
7
8
9
0
DATE
START
DEBUT
PR
2
4
1
3
ENTER/ENTR
EE
EXPRESS
SAT
24H EXPRESS
PR
/
PUSH / TURN
2
3
3
1
VCR
SAT
REVIEW
g e n e r a l
Power requirement
: AC 220 V ­ 240 V
Ó, 50 Hz/60 Hz
Power consumption
: on : 16 W, off : 4.0 W
Operating Temperature
: 5°C to 40°C
Storage Temperature
: ­20°C to 60°C
Operating position
: Horizontal only
Dimensions (WxHxD)
: 400 mm x 94 mm x 278 mm
Weight
: 3.4 kg
Format
: VHS PAL standard
Maximum recording time
(SP)
: 240 min. with E-240 video cassette
(LP)
: 480 min. with E-240 video cassette
v i d e o / a u d i o
Signal system
: PAL-type colour signal and CCIR monochrome signal,
625 lines/50 fields
Recording system
: DA4 (Double Azimuth) helical scan system
Signal-to-noise ratio
: 45 dB
Horizontal resolution
: 250 lines
Frequency range
: 70 Hz to 10,000 Hz (Normal audio)
20 Hz to 20,000 Hz (Hi-Fi audio)
Input/Output
: 21-pin SCART connectors (IN/OUT x 1, IN/DECODER x 1)
RCA connectors (AUDIO OUT x 1)
t u n e r / t i m e r
TV channel storage capacity: 99 positions (+AUX position)
Tuning system
: Frequency synthesized tuner
Channel coverage
: VHF 44.5 MHz ­ 143 MHz/
143 MHz ­ 470 MHz/
UHF 470 MHz ­ 862 MHz
Aerial output
: UHF channels 22 ­ 69 (Adjustable)
Memory backup time
: Approx. 10 min.
a c c e s s o r i e s
Provided accessories
: RF cable, Satellite Controller,
Infrared remote control unit,
`AA' battery x 2
Specifications shown are for SP mode unless otherwise specified.
E.& O.E. Design and specifications subject to change without notice.


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TABLE OF CONTENTS
Section
Title
Page
Section
Title
Page
2.2.24 Rotor assembly ........................................................... 2-14
2.2.25 Upper drum assembly ................................................. 2-15
2.3 Compatibility adjustment .................................................... 2-16
2.3.1 FM waveform linearity ................................................... 2-16
2.3.2 Height and tilt of the A/C head ....................................... 2-17
2.3.3 A/C head phase (X-value) ............................................. 2-17
2.3.4 Standard tracking preset ............................................... 2-18
2.3.5 Tension pole position ..................................................... 2-18
3. ELECTRICAL ADJUSTMENT
3.1 Precaution ............................................................................ 3-1
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
3.2 Servo circuit .......................................................................... 3-2
3.2.1 Switching point ................................................................ 3-2
3.2.2 Slow tracking preset ........................................................ 3-2
3.3 Video circuit .......................................................................... 3-2
3.3.1 Auto picture initial setting ................................................ 3-2
3.4 Syscon circuit [HR-J680EU/J780EU] ................................... 3-2
3.4.1 Timer clock ...................................................................... 3-2
4. CHARTS AND DIAGRAMS
NOTES OF SCHEMATIC DIAGRAM .......................................... 4-1
CIRCUIT BOARD NOTES ........................................................... 4-2
4.1 BOARD INTERCONNECTIONS .......................................... 4-3
4.2 MAIN(VIDEO/AUDIO) SCHEMATIC DIAGRAM ................... 4-5
4.3 MAIN(ON SCREEN) SCHEMATIC DIAGRAM ..................... 4-7
4.4 MAIN(SYSCON) SCHEMATIC DIAGRAM ........................... 4-9
4.5 MAIN(SW.REG) SCHEMATIC DIAGRAM ........................... 4-11
4.6 MAIN(TUNER) SCHEMATIC DIAGRAM ............................ 4-13
4.7 MAIN(FRONT) AND ADV.JOG SCHEMATIC DIAGRAMS . 4-15
4.8 MAIN(TERMINAL), SAT CTL AND R.PAUSE SCHEMATIC
DIAGRAMS ........................................................................ 4-17
4.9 REMOTE CONTROLLER SCHEMATIC DIAGRAM ........... 4-19
4.10 MAIN, SAT CTL AND R.PAUSE CIRCUIT BOARDS ....... 4-21
4.11
FDP GRID ASSIGNMENT AND ANODE CONNECTION 4-23
4.12 WAVEFORMS .................................................................. 4-24
4.13 VOLTAGE CHARTS ......................................................... 4-25
4.14 CPU PIN FUNCTION ....................................................... 4-26
4.15 SYSTEM CONTROL BLOCK DIAGRAM ......................... 4-27
4.16 VIDEO BLOCK DIAGRAM ............................................... 4-29
4.17 AUDIO BLOCK DIAGRAM .............................................. 4-31
5. PARTS LIST
5.1 PACKING AND ACCESSORY ASSEMBLY <M1> ............... 5-1
5.2 FINAL ASSEMBLY <M2> .................................................... 5-2
5.3 MECHANISM ASSEMBLY <M4> ........................................ 5-4
5.4 ELECTRICAL PARTS LIST .................................................. 5-6
MAIN BOARD ASSEMBLY <03> ............................................... 5-6
A/C HEAD BOARD ASSEMBLY <12> ..................................... 5-13
ADV.JOG BOARD ASSEMBLY(HR-J780EU/J785EK) <38> ... 5-13
LOADING MOTOR BOARD ASSEMBLY <55> ....................... 5-13
R.PAUSE BOARD ASSEMBLY(HR-J780EU)<91> ................. 5-13
SAT_CTL BOARD ASSEMBLY <92> ...................................... 5-13
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 set the "Service position" ..................................... 1-4
1.5 Mechanism service mode ..................................................... 1-4
1.5.1 How to set the "Mechanism service mode" ..................... 1-4
1.6 Jig RCU mode ....................................................................... 1-4
1.6.1 Setting the Jig RCU mode ............................................... 1-4
1.6.2 Setting the User RCU mode ............................................ 1-4
1.7 Emergency display function ................................................. 1-5
1.7.1 Displaying the EMG information ...................................... 1-5
1.7.2 Clearing the EMG history ................................................ 1-5
1.7.3 EMG content description ................................................. 1-6
1.7.4 EMG detail information <1> ............................................. 1-7
1.7.5 EMG detail information <2> ............................................. 1-8
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 ............................ 2-2
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" .............. 2-6
2.2.3 Cassette holder assembly ............................................... 2-6
2.2.4 Pinch roller arm assembly ............................................... 2-8
2.2.5 Guide arm assembly and press lever assembly .............. 2-8
2.2.6 A/C head ......................................................................... 2-8
2.2.7 Loading motor ................................................................. 2-8
2.2.8 Capstan motor ................................................................. 2-9
2.2.9 Pole base assembly (supply or take-up side) .................. 2-9
2.2.10 Rotary encoder ........................................................... 2-10
2.2.11 Clutch unit ................................................................... 2-10
2.2.12 Change lever assembly, direct gear, clutch gear and
coupling gear .............................................................. 2-10
2.2.13 Link lever ..................................................................... 2-11
2.2.14 Cassette gear, control cam and worm gear ................. 2-11
2.2.15 Control plate ................................................................ 2-11
2.2.16 Loading arm gear (supply or take-up side) and
loading arm gear shaft ................................................ 2-12
2.2.17 Take-up lever, take-up head and control plate guide .. 2-13
2.2.18 Capstan brake assembly ............................................ 2-13
2.2.19 Sub brake assembly (take-up side) ............................ 2-13
2.2.20 Main brake assembly (take-up side), reel disk (take-up side)
and main brake assembly (supply side) ................................ 2-13
2.2.21 Tension brake assembly, reel disk (supply side) and
tension arm assembly ................................................. 2-14
2.2.22 Idler lever, idler arm assembly .................................... 2-14
2.2.23 Stator assembly .......................................................... 2-14
HR-J680EK
HR-J680EU
HR-J780EU
HR-J785EK
JOG/SHUTTLE
NOT USED
NOT USED
USED
USED
VIDEO SYSTEM
PAL
PAL/MESECAM(MANUAL)
PAL/MESECAM(MANUAL)
PAL
BROADCASTING STANDARD
I
B/G,D/K
B/G,D/K
I
STEREO DECODER
NICAM
NICAM/A2
NICAM/A2
NICAM
RF OUT SYSTEM [INITIAL]
I
G,K
G,K
I
VCR PLUS+
VIDEOPLUS+ DELUXE
SHOWVIEW DELUXE
SHOWVIEW DELUXE
VIDEOPLUS+ DELUXE
LANGUAGE [INITIAL] (ON SCREEN DISPLAY)
ENG
13LANG.[ENG]
13LANG.[ENG]
ENG
AUDIO DUBBING/OPERATION
NOT USED
NOT USED
USED/BUTTON
NOT USED
FRONT VIDEO/AUDIO IN
NOT USED
NOT USED
USED
NOT USED
WINDOW COLOR
SMOKE LIGHT GRAY
SMOKE LIGHT GRAY
BLUE
SMOKE LIGHT GRAY
REMOTE PAUSE
NOT USED
NOT USED
USED
NOT USED
CABLE MOUSE
PROVIDED
OPTION
OPTION
PROVIDED
The following table lists the differing points between Models ( HR-J680EK, HR-J680EU, HR-J780EU and HR-J785EK) in this series.


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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 in-
scriptions on the cabinet, chassis and certain parts of the product.
When performing service, be sure to read and comply with these
and other cautionary notices appearing in the operation and serv-
ice 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 compli-
ance 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 trans-
former primary lead wires are performed using crimp type connec-
tors, if replacing the connectors is unavoidable, in order 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.
I
·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.
1.2
5
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 compliance with safety
standards.
1. Insulation resistance test
Confirm the specified insulation resistance or greater between power cord plug prongs and exter-
nally 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 acces-
sible 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 accessible
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.
II
S40888-01
ab
c
V
A
Externally
exposed
accessible part
Z


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1-1
[1]
Top cover,
D1 4(S1a), (S1b)
Bracket
2(S1c)
[2]
Front panel assembly
D2 CN7001(WR2a)
<Note 2a>
[HR-J780EU/J785EK], <Note 2b>
4(L2a), 3(L2b)
<Note 2c>
ADV. Jog board assembly
2(S2a)
[3]
Drum assembly
D3 CON1(WR3a),
<Note 2c>
CN1(WR3b),
(S3a), (S3b), (S3c)
(Drum shield)
2(S3d)
[4]
Mechanism assembly D4 CN2001(WR4a),
<Note 2c>
(S4a),(S4b),
<Note 4a>
(S4c), (S4d)
[5]
Main board assembly
D5 6(L5a),
<Note 2c>
(S5a), 3(S5b), (S5c)
[6]
Bottom cover
D6 2(L6a), 9(L6b)
<Note 6a>
SECTION 1
DISASSEMBLY
1.3 Disassembly/assembly method
1.1 Disassembly flow chart
This flowchart lists the disassembling steps for the cabinet
parts and P.C. boards in order to gain access to item(s) to
be serviced. When reassembling, perform the step(s) in re-
verse order. Bend, route and dress the flat cables as they
were originally laid.
1.2 How to read the disassembly and assembly
Note:
·
The bracketed ( ) WR of the connector symbol are as-
signed nos. in priority order and do not correspond to
those on the spare parts list.
(5) Adjustment information for installation
Top cover, Bracket
Front panel assembly
Drum assembly
Mechanism assembly
Main board assembly
Bottom cover
[1]
[2]
[3]
[4]
[5]
[6]
Step/
LocNo.
Part Name
Fig.
No.
Point
Note
-----------------
(1)
(2)
(3)
(4)
(5)
Step/
LocNo.
Part Name
Fig.
No.
Point
Note
[1]
Top cover,
D1 4(S1a),(S1b),3(L1a),
<Note 1a>
2(SD1a),(P1a),(W1a),
CN1(WR1a),
Bracket
2(S1c)
<Example>
(1) Order of steps in Procedure
When reassembling, perform the step(s) in the reverse order.
These numbers are also used as the identification (location) No.
of parts Figures.
(2) Part name to be removed or installed.
(3) Fig. No. showing procedure or part location.
(4) Identification of part to be removed, unhooked, unlocked,
released, unplugged, unclamped or unsoldered.
P= Spring, W= Washer, S= Screw, L= Locking tab, SD= Solder,
CN**(WR**)= Remove the wire (WR**) from the connector
(CN**).
<Note 2a>
· When reattaching the Front panel assembly, make sure that
the door opener "a" of the Cassette holder assembly is low-
ered in position prior to the reinstallation.
<Note 2b>
· When reattaching the Front panel assembly, pay careful at-
tention to the switch lever not to make it touch the switch
knob "b" of the Main board assembly from the side.
<Note 2c>
· Be careful not to damage the connector and wire etc. during
connection and disconnection.
When connecting the wire to the connector, be careful with
the wire direction.
<Note 4a>
· When it is required to remove the screws (S4a to S4b) re-
taining the Mechanism assembly, please refer to the "Pro-
cedures for Lowering the Cassette holder assembly"(See
on page 1-2).
· When reattaching the Mechanism assembly to the Main
board assembly, take care not to damage the sensors on
the Main board assembly.
· When removing the Mechanism assembly only, unhook the
two spacers connecting it with the Main board assembly
with pliers from the back side of the Main board assembly
first, and then remove the Mechanism assembly.
· The wire (WR4a) has excess length that may be loose, as it
is quite long. After inserting the wire and connectors, the
loose portion of the wire should be taken up and accommo-
dated between the A/C head base and the main deck.
<Note 6a>
When removing the bottom cover, push down the two tabs
(L6a) to slide the bottom cover.
-----------------
-----------------