JVC GR-AX970UM Service Manual

SERVICE MANUAL

COMPACT VHS CAMCORDER

JVC SERVICE & ENGINEERING COMPANY OF AMERICA

DIVISION OF JVC AMERICAS CORP.

Head office
East Coast
Midwest
West Coast
Atlanta
Hawaii

1700 Valley Road Wayne, New Jersey 07470-9976

:

10 New Maple Avenue Pine Brook, New Jersey 07058-9641

:

705 Enterprise Street Aurora, Illinois 60504-8149

:

5665 Corporate Avenue Cypress, California 90630-0024

:

1500 Lakes Parkway Lawrenceville, Georgia 30043-5857

:

2969 Mapunapuna Place Honolulu, Hawaii 96819-2040

:

[phone]
[phone]
[phone]
[phone]
[phone]
[phone]

JVC CANADA INC.

Head office
Montreal
Vancouver

:

21 Finchdene Square Scarborough, Ontario M1X 1A7

:

16800 Rte Trans-Canadienne, Kirkland, Quebec H9H 5G7

:

13040 Worster Court Richmond, B.C. V6V 2B3

[phone]
[phone]
[phone]

S40895-04

GR-AX770U/AX970U

SPECIFICATIONS

General

Format : VHS NTSC standard
Power source : DC 11 V (Using AC Adapter)

Power consumption

Viewfinder on : 3.7 W
Signal system : NTSC-type
Video recording system

Luminance : FM recording

Color : Converted sub-carrier direct recording

Cassette : cassette
Tape speed

SP : 33.35 mm/sec. (1-5/16 ips)

EP : 11.12 mm/sec. (7/16 ips)
Recording time (max.)

SP : 40 minutes

EP : 120 minutes

Operating

temperature : 0°C to 40°C (32°F to 104°F)
Operating humidity : 35% to 80%
Storage temperature : –20°C to 50°C (–4°F to 122°F)
Weight : Approx. 850 g (1.9 lbs)

No. 86663

Dimensions : 200 mm x 112 mm x 115 mm

(W x H x D) (7-7/8" x 4-7/16" x 4-9/16")
Pickup : 1/4" format CCD
Lens : F1.6, f = 3.9 mm to 62.4 mm,

Viewfinder : Electronic viewfinder with 0.5" black/white CRT
White balance

adjustment : Auto/Manual adjustment

GR-AX770U/AX970U

(The specifications shown pertain specifically to the model GR-AX770)

Camcorder

DC 6 V (Using battery pack)

Conforms to VHS standard

(with TC-40 cassette)

16:1 power zoom lens with auto iris and macro control,
filter diameter 40.5 mm

Connectors

Video : 1 V (p-p), 75 Ø unbalanced, analog output (via

Audio : 300 mV (rms), 1 kØ analog output

Power requirement

U.S.A. and Canada : AC 120 V`, 60 Hz
Other countries : AC 110 V to 240 V`, 50 Hz/60 Hz

Output : DC 11 V , 1 A

Optional Accessories

• Battery Packs BN-V12U, BN-V20U, BN-V400U

• A/V (Audio/Video) Cable

• Compact VHS ( ) Cassettes TC-40/30/20

• Active Carrying Bag CB-V7U

Some accessories are not available in some areas. Please consult
your nearest JVC dealer for details on accessories and their
availability.

Specifications shown are for SP mode unless otherwise indicated.
E & O.E. Design and specifications subject to change without notice.

Video output connector)

(via Audio output connector)

AC Adapter

Printed in Japan

This service manual is printed on 100% recycled paper.

COPYRIGHT © 2002 VICTOR COMPANY OF JAPAN, LTD.

No. 86663

January 2002

TABLE OF CONTENTS

Section Title Page Section Title Page

Important Safety Precautions

INSTRUCTIONS

1. DISASSEMBLY

1.1 SERVICE CAUTIONS ............................................................ 1-1

1.1.1 Precautions ...................................................................... 1-1

1.1.2 How to read the disassembly and assembly ................... 1-1

1.1.3 Connection of the wires .................................................. 1-1

1.2 TOOLS REQUIRED FOR ADJUSTMENTS ........................... 1-2

1.3 DISASSEMBLY/ASSEMBLY OF CABINET PARTS................ 1-3

1.3.1 Disassembly flow chart ................................................... 1-3

1.3.2 Disassembly method ....................................................... 1-4

1.4 DISASSEMBLY/ASSEMBLY OF CAMERA SECTION AND

DECK SECTION .................................................................... 1-8

1.4.1 Flowchart of disassembly ................................................ 1-8

1.4.2 Disassembly method ....................................................... 1-8

1.5 REPLACEMENT OF 3 CCD IMAGE SENSOR ................... 1-10

1.5.1 Removal of CCD image sensor ..................................... 1-10

1.5.2 Installation of new CCD image sensor .......................... 1-10

1.5.3 Replacement of CCD board assembly .......................... 1-10

1.6 TAKE OUT CASSETTE TAPE .............................................. 1-11

1.7 EMERGENCY DISPLAY ...................................................... 1-12

1.8 DEMONSTRATION MODE ................................................. 1-12

1.9 SERVICE NOTE .................................................................. 1-14

2. MECHANISM ADJUSTMENT

2.1 SERVICE CAUTIONS ............................................................ 2-1

2.1.1 Precautions ...................................................................... 2-1

2.1.2 How to read the disassembly and assembly

(For Mechanism Parts) .................................................... 2-1

2.1.3 Required adjustment tools .............................................. 2-1

2.2 DISASSEMBLY/ASSEMBLY OF MECHANISM PARTS ........ 2-2

2.3 CHECKUP AND ADJUSTMENT OF MECHANISM PHASE .. 2-6

2.4 TAPE TRANSPORT ADJUSTMENT ...................................... 2-7

2.4.1 Back tension .................................................................... 2-7

2.4.2 Tape pattern ..................................................................... 2-7

2.4.3 A/C head height & azimuth .............................................. 2-8

2.4.4 Phase of control head (X value) ....................................... 2-9

2.5 REMARKS ............................................................................ 2-9

2.5.1 Cleaning ........................................................................... 2-9

2.5.2 Applying oil and grease ................................................... 2-9

2.5.3 Checkup .......................................................................... 2-9

2.6 JIG CONNECTOR CABLE CONNECTION .......................... 2-10

4. CHARTS AND DIAGRAMS

NOTES OF SCHEMATIC DIAGRAM .......................................... 4-1

CIRCUIT BOARD NOTES ........................................................... 4-2

4.1 BOARD INTERCONNECTIONS .......................................... 4-3

4.2 CPU SCHEMATIC DIAGRAM .............................................. 4-5

4.3 M. MDA SCHEMATIC DIAGRAM ......................................... 4-7

4.4 VTR ASP SCHEMATIC DIAGRAM....................................... 4-9

4.5 DSP SCHEMATIC DIAGRAM............................................. 4-11

4.6 F/Z/I/MDA SCHEMATIC DIAGRAM .................................... 4-13

4.7 V OUT SCHEMATIC DIAGRAM ......................................... 4-15

4.8 TG/CDS SCHEMATIC DIAGRAM ...................................... 4-17

4.9 REG SCHEMATIC DIAGRAM ............................................ 4-19

4.10 LCD/CVF SCHEMATIC DIAGRAM [GR-AX970U] ........... 4-21

4.11 BW/CVF SCHEMATIC DIAGRAM [GR-AX770UC] .......... 4-23

4.12 BW/CVF SCHEMATIC DIAGRAM [GR-AX970U] ............ 4-25

4.13 JACK SCHEMATIC DIAGRAM ........................................ 4-27

4.14 CCD SCHEMATIC DIAGRAM .......................................... 4-29

4.15 C-VF BL SCHEMATIC DIAGRAM [GR-AX970U] ............. 4-30

4.16 C-VF SHEMATIC DIAGRAM [GR-AX970U] ..................... 4-31

4.17 E.VF SCHEMATIC DIAGRAM [GR-AX770UC] ................ 4-33

4.18 TOP OPE UNIT, ZOOM UNIT, REAR UNIT AND SENSOR

SCHEMATIC DIAGRAMS ................................................ 4-35

4.19 MAIN CIRCUIT BOARD................................................... 4-37

4.20 CCD CIRCUIT BOARD .................................................... 4-43

4.21 E. VF CIRCUIT BOARD [GR-AX770UC] ......................... 4-44

4.22 C-VF CIRCUIT BOARD [GR-AX970U] ............................ 4-45

4.23 WAVEFORMS .................................................................. 4-46

4.24 VOLTAGE CHARTS ......................................................... 4-47

4.25 POWER SYSTEM BLOCK DIAGRAM............................. 4-51

4.26 CAMERA AND Y/C SYSTEM BLOCK DIAGRAM ........... 4-53

4.27 CPU/MDA SYSTEM BLOCK DIAGRAM.......................... 4-57

5. PARTS LIST

5.1 PACKING AND ACCESSORY ASSEMBLY <M1> ................ 5-1

5.2 FINAL ASSEMBLY <M2> .................................................... 5-3

5.3 MECHANISM ASSEMBLY <M3> ....................................... 5-6

5.4

ELECTRONIC VIEWFINDER ASSEMBLY <M4> [GR-AX770UC] ...

5.4

ELECTRONIC VIEWFINDER ASSEMBLY <M4> [GR-AX970U] .....

5.5 ELECTRICAL PARTS LIST .................................................. 5-10

MAIN BOARD ASSEMBLY <01> ..................................................

CCD BOARD ASSEMBLY <02> ......................................... 5-16

C-VF BL BOARD ASSEMBLY <06>[AX970U] .................... 5-16

E.VF BOARD ASSEMBLY <60>[AX770UC] ....................... 5-16

5-8
5-9

5-10

3. ELECTRICAL ADJUSTMENT

3.1 ELECTRICAL ADJUSTMENT................................................ 3-1

3.1.1 Preparation ...................................................................... 3-1

3.2 ELECTRONIC VIEWFINDER (E. VF) ADJUSTMENT

[B/W VF model only] ............................................................... 3-2

3.2.1 Tilt .................................................................................... 3-2

3.2.2 Centering ......................................................................... 3-2

3.2.3 Vertical scanning .............................................................. 3-2

3.2.4 Brightness ....................................................................... 3-2

3.2.5 Focus ............................................................................... 3-2

The following table lists the differing points between Models GR-AX770U and GR-AX970U in this serise.

GR-AX770U GR-AX970U

E.VF B/W COLOR

DC LIGHT NOT USED USED

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.

Precautions during Servicing

•

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 comply 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.

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 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).

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.1

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.

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 cath­ode 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.

Fig.4

(3) Align the lengths of the wires to be connected. Insert the

wires fully into the connector.

Metal sleeve

Connector

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

.2

5

2

.0

5

.5

Fig.6

(5) Check the four points noted in Fig.7.

Not easily pulled free

Wire insulation recessed

more than 4 mm

Fig.7

Crimping tool

Crimped at approx. center

of metal sleeve

Conductors extended

I

S40888-01

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 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’) be­tween soldered terminals, and between terminals and surrounding metallic parts. See table 1
below.

Fig. 8

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.

Externally
exposed
accessible part

Fig. 9

Z

V

ab

A

c

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

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

SECTION 1

DISASSEMBLY

1.1 SERVICE CAUTIONS

1.1.1 Precautions

1. Before disassembling/re-assembling the set as well as
soldering parts, make sure to disconnect the power ca­ble.

2. When disconnecting/connecting connectors, pay enough
attention to wiring not to damage it.

3. In general, chip parts such as resistor, shorting jumpers
(0-ohm resistor), ceramic capacitors, diodes, etc. can not
be reused after they were once removed.

4. When installing parts, be careful not to do with other parts
as well as not to damage others.

5. When removing ICs, be careful not to damage circuit pat­terns.

6. Tighten screws properly during the procedures. Un­less specified otherwise, tighten screws at torque of

0.196 N

•

m (2.0 kgf•cm).

1.1.2 How to read the disassembly and assembly

(For Cabinet Parts)

REMOVAL

STEP

No.

1

2
3

(1) (2) (3) (4)

PART

CASETTE COVER C1 (S1), 3(L1a), (L1b), (L1c),
ASSEMBLY Push button, Spring

UPPER CASE C2 2(S2), 2(L2)
LOWER CASE C3 9(S3), (L3a), (L3b), CN3a,

ASSEMBLY COVER(JACK)
(Incl. E.VF ASSEMBLY)

Fig.

No.

*UNLOCK/RELEASE/
UNPLUG/UNCLAMP/

UNSOLDER

(1) Order of steps in Procedure

When reassembling, preform the step(s) in the reverse
order. These numbers are also used as the identifica-

tion (location) No. of parts Figures.
(2) Part to be removed or installed.
(3) Fig. No. showing Procedure or Part Location.

C = Cabinet

CA = Camera

D = Deck

(4) Identification of part to be removed, unhooked, un-

locked, released, unplugged, unclamped or unsoldered.

P = Spring

W = Washer

S = Screw

* = Unhook, unlock, release, unplug or unsolder.

2(S3) = 2 Screws (S3)

CN = Connector

1.1.3 Connection of the wires

Pull both ends of the connector in the arrow direction, re­move the lock and disconnect the flat wire.

Wire

Connector

Fig. 1-1-1

Extend the locks in the direction of the arrow for unlocking
and then pull out the wire.

Wire

Connector

NOTE:

After removing the wire, return the stopper to
its original position, because it is apt to come
off if it is left open.

Fig. 1-1-2

1-1

1.2 TOOLS REQUIRED FOR ADJUSTMENTS

Alignment tape

(for SP interchangeability)

1

MHP-C

Alignment tape

(for N. SP PB Y/C level)

2

MHV-2C

Service support system

YTU94057-56

1615

PC cable

QAM0099-002

3

5

78

910

Torque driver

YTU94088

INF adjustment lens

YTU92001B

Gray Scale Chart

YTU94133A

INF lens holder

YTU94087

4

6

Light box Assembly

Bit

YTU94088-003

Conn. ring

YTU92001-111

Color Bar Chart

YTU94133C

YTU93096A

17

Cleaning cloth

KSMM-01

Table 1-2-1

11 12

13

Camera stand

YTU93079

Jig connector cable

YTU93106A

1-2

Extension connector

YTU94145B-30

Communication cable

14

YTU93107A

1,2. Alignment tape

To be used for check and adjustment of interchange­ability of the mechanism.
(Video: Color bar signal, Audio: Non-signal)

3. Torque driver

Be sure to use to fastening the mechanism and exte­rior parts because those parts must strictly be control­led for tightening torque.

4. Bit

This bit is slightly longer than those set in conventional
torque drivers.

1.3 DISASSEMBLY/ASSEMBLY OF CABINET PARTS

1.3.1 Disassembly flow chart

This flowchart indicates the disassembly step for the cabi­net parts and board assembly in order to gain access to
item(s) to be serviced. When reassembling, perform the
step(s) in reverse order. Bend, route and dress the flat ca­bles as they were originally.

1

2

Cassette cover assembly

Upper case

5. INF adjustment lens

To be used for adjustment of the camera system.

6. Conn. ring

The connector ring to attach the INF. lens to the head
of the OP lens.

7. Gray scale chart

To be used for adjustment of the camera system.

8. Color bar chart

To be used for adjustment of the camera system.

9. INF lens holder

To be used together with the camera stand (11) for op­erating the VideoMovie in the stripped-down condition
such as the status without the exterior parts or for us­ing commodities that are not yet conformable to the in­terchangeable ring.

10. Light box assembly

To be used for adjustment of the camera system.

11. Camera stand

To be used together with the INF adjustment lens
holder.

12. Extention connector

To be used to JIG connector cable

13. JIG connector cable

Connected to CN25 of the main board and used for
measuring error rates, etc.

Lower case assembly

3

4

5

6

7

8

9

0

!

Note :

For screw management, refer to the table appearing
in the section “1.9 SERVICE NOTE” (page 1-14).

(Incl. E.VF assembly)

E.VF assembly

Top operation unit

Rear unit

Front cover assembly

(Incl. Microphone / Cover(light) )

Microphone

Cover(light)

Upper Cover(s) assembly

Front frame assembly

14. Communication Cable

Connect the Communication cable between the PC ca­ble and Jig connector cable when performing a PC ad­justment.

15. Service support system

To be used for adjustment with a personal computer.

16. PC cable

To be used to connect the VideoMovie and a personal
computer with each other when a personal computer
isused for adjustment.

17. Cleaning cloth

Recommended cleaning cloth to wipe down the video
heads, mechanism (tape transport system), optical lens
surface.

1-3

1.3.2 Disassembly method

STEP

/LOC

No.

1

2
3

4
5

6
7

8
9

0

!

PART

CASETTE COVER C1 (S1), 3(L1a), (L1b), (L1c),
ASSEMBLY Push button, Spring

UPPER CASE C2 2(S2), 2(L2)
LOWER CASE C3 9(S3), (L3a), (L3b), CN3a,

ASSEMBLY COVER(JACK)
(Incl. E.VF ASSEMBLY)

E.VF ASSEMBLY C4 3(S4)
TOP OPERATION C5 2(S5),(L5a),(L5b),2(L5c),

UNIT *CN5a
REAR UNIT C6 3(S6),(L6a),(L6b),*CN6a
FRONT COVER C7 2(S7a),(S7b),(L7a),(L7b),

ASSEMBLY *CN7a
(Incl. MICROPHONE /
COVER (LIGHT) )

MICROPHONE (S7a)
COVER (LIGHT) / 2(L7c)

DC LIGHT
UPPER COVER(S) C8 2(S8a),(S8b)

ASSEMBLY
FRONT FRAME C9 2(S9)

ASSEMBLY

Fig.
No.

List of Abbreviations:

2(S1)=2 screws (S1)
4(L1a)=4 Locking Tabs
CN=Connector

REMOVAL

*UNLOCK/RELEASE/
UNPLUG/UNCLAMP/

UNSOLDER

(L1b)

(L1a)

(L1c)

Spring

Push button

1

(S1)

1

Reference Notes:
<NOTE 1>
Destination of connectors

Note :

Two kinds of double-arrows in connection tables
respectively show kinds of connector/wires.

⇔ : Flat wire

←→ : Wire

Con-

No.of

nector

CN3a

CN5a 12 TOP OPERATION UNIT ⇔ MAIN CN18

CN6a 13 REAR UNIT ⇔ MAIN CN28

CN7a 2 MIC ←→ MAIN CN8

Pins

3 E.VF (B/W) ←→ MAIN CN12

20 C-VF CN7701 / C-VF BL CN7801 ⇔ MAIN CN11

Connector

<NOTE 2, 3>
(1) The FPC assembly should be winded around the hinge

assembly by two and half turns so that the wire to be
connected to the monitor board assembly is posi­tioned inside.

(2) The upper and lower hinge covers should be mounted

so carefully the any wire is not caught into either of the
covers.

2

(S2)

(L2)

(S2)

Fig. C1

2

3

1-4

Fig. C2

(S )

5

3

(S )

6

3

(S )

(S )

7

3

8

3

COVER

(JACK)

4

3

(S )

12

(S )

(L b)

(S )

3

3

CN a

3

(L a)

3

9

3

11

3

(S )

(S )

3

10

3

Fig. C3

(L5c)

5

15

4

(S )

13

4

(S )

14

4

(S )

17

(S5)

16

(S5)

(L5a)

(L5b)

4

Fig. C4

CN5a

Fig. C5

1-5