JVC HM-DH3000 Service Manual

SERVICE MANUAL

D-VHS DIGITAL RECORDER

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

(973)315-5000 (973)396-1000 (630)851-7855 (714)229-8011 (770)339-2582 (808)833-5828

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

(416)293-1311 (514)871-1311 (604)270-1311

S40895-03

HM-DH30000U

SPECIFICATIONS

GENERAL

Power requirement : AC 120 V`, 60 Hz Power consumption

Temperature

Operating position : Horizontal only Dimensions (W x H x D) : 435 mm x 105 mm x 383 mm

Weight : 5.7 kg (12.6 lbs) Maximum recording time

VIDEO/AUDIO (D-VHS)

Video format : MPEG2 standard Audio format : Encode MPEG1 Layer2

Track composition

No. 82894

Recording specification

Interface : IEEE1394 compliant

HM-DH30000U

A.MONITOR

VCR TVCABLE/DBS

POWER

A/B DISPLAY

TV/VCR

ENTER/OSD

123

. , ?

ABC DEF

456

GHI JKL MNO

DBS

DAILY(M-F)

WEEKLY

PQRS TUV WXYZ

C. RESET

AUX

CANCEL

TIMER

START STOP DATE

EXPRESS PROGRAMMING

PROG.

HS/STD/LS3

SKIP SEARCH

PROG.

CHECK

SP/EP

BACK

PLAY

F F

REW

STOP

P A

TV CH +

VOL

–

TV CH –

JOG/

SHUTTLE

POWER

PULL-OPEN

Power on : 55 W Power off : 18 W

Operating : 5°C to 40°C (41°F to 104°F) Storage : –20°C to 60°C (–4°F to140°F)

(17-3/16" x 4-3/16" x 15-1/8")

D-VHS (HS) : 210 min. with DF-420 video cassette D-VHS (STD) : 420 min. with DF-420 video cassette D-VHS (LS3) : 1260 min. with DF-420 video cassette S-VHS/VHS (SP) : 210 min. with ST-210 video cassette S-VHS/VHS (EP) : 630 min. with ST-210 video cassette

Decode MPEG1 Layer2

Dolby Digital

Tape speed : 33.4 mm/sec (HS mode)

16.67 mm/sec (STD mode)

5.55 mm/sec (LS3 mode) Head azimuth : ±30 deg Drum rotation : 1800 rpm Tracking system : CTL track system

Main data input rate : 28.2 Mbps (HS mode)

14.1 Mbps (STD mode)

4.7 Mbps (LS3 mode)

DTCP digital copy protection compatible

REC LINK

TIMER STOP/EJECT PLAY

MTP NTSC

VIDEO/AUDIO (S-VHS/VHS)

Format : S-VHS/VHS NTSC standard 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 Frequency range

Normal audio : 70 Hz to 10,000 Hz Hi-Fi audio : 20 Hz to 20,000 Hz

TUNER

Tuning system : Frequency-synthesized tuner Channel coverage

VHF : Channels 2–13 UHF : Channels 14–69 CATV : 113 Channels

TIMER

Clock reference : Quartz Program capacity : 1-year programmable timer/24 programs Memory backup time : Approx. 60 min.

CONNECTORS

Input/Output : i.LINK IN/OUT, DV IN x 2 (4-pin, S200)

RCA connectors (IN x 3, OUT x 2)

S-video connectors (IN x 3, OUT x 2)

Component video OUT (Y, PB/CB, PR/CR) x 1

Digital OUT (optical) x 1

ACCESSORIES

Provided accessories :

Infrared remote control unit, “AA” battery x 2,

Audio cable, RF cable (F-type),

S-video cable (4-pin), Controller

䡲 Manufactured under license from Dolby Laboratories.

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

Printed in Japan

This service manual is printed on 100% recycled paper.

No. 82894

August 2001

Section Title Page Section Title Page

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 ............................................................................ 1-5

1.4.1 How to set the “Service position” ........................................... 1-5

1.4.2 Precautions for cassette loading in the “Service position” ..... 1-5

1.4.3

Cassette loading and ejection methods in the “Service position”

1.5 Mechanism service mode ............................................................ 1-6

1.5.1 How to set the “Mechanism service mode” ............................ 1-6

1.6 Jig RCU mode ............................................................................. 1-6

1.6.1 Setting the Jig RCU mode ..................................................... 1-6

1.6.2 Setting the User RCU mode .................................................. 1-6

1.7 Opening on the chassis ................................................................ 1-6

1.8 Emergency display function ......................................................... 1-7

1.8.1 Displaying the EMG information ............................................. 1-7

1.8.2 Clearing the EMG histor y ....................................................... 1-7

1.8.3 EMG content description ........................................................ 1-8

1.8.4 EMG detail information <1> ................................................... 1-9

1.8.5 EMG detail information <2> ................................................. 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 ................................... 2-2

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..

2.2.13 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) ................................................

2.2.21 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

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

3.1.5 EVR Adjustment ..................................................................... 3-1

3.2 Servo circuit ................................................................................. 3-2

3.2.1 Switching point ....................................................................... 3-2

3.2.2 D-VHS switching point ........................................................... 3-2

3.2.3 Slow tracking preset ............................................................... 3-2

1-5

2-10

2-13

3.3 Video circuit .................................................................................. 3-3

3.3.1 D/A level ................................................................................. 3-3

3.3.2 EE Y/PB Y (S-VHS/VHS) level ............................................... 3-3

3.3.3 REC color (colour) level ......................................................... 3-3

3.3.4 Video EQ (Frequency response) ............................................ 3-4

3.3.5 Auto picture initial setting ....................................................... 3-4

3.4 Audio circuit .................................................................................. 3-4

3.4.1 Audio REC FM ....................................................................... 3-4

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 ............................................................................. 3-5

3.5.4 Separation - 1 ......................................................................... 3-6

3.5.5 Separation - 2 ......................................................................... 3-6

3.5.6 SAP VCO ............................................................................... 3-6

3.6 Digital circuit ................................................................................. 3-6

3.6.1 D-VHS REC level ................................................................... 3-6

3.6.2 PLL f0 ..................................................................................... 3-7

4. CHARTS AND DIAGRAMS

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

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

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

4.2

REGULATOR AND SUB REGULATOR SCHEMATIC DIAGRAMS ......

4.3 MAIN (VIDEO/AUDIO) SCHEMATIC DIAGRAM .......................... 4-7

4.4 MAIN (SYSCON) SCHEMATIC DIAGRAM .................................. 4-9

4.5 MAIN (TUNER/DEMOD) SCHEMATIC DIAGRAM ..................... 4-11

4.6 MAIN (AUDIO I/O) SCHEMATIC DIAGRAM .............................. 4-13

4.7 MAIN (SYNCDET) SCHEMATIC DIAGRAM .............................. 4-15

4.8 MAIN (MAIN-TERMINAL) SCHEMATIC DIAGRAM ................... 4-17

4.9 3D DIGITAL/4M SCHEMATIC DIAGRAM................................... 4-19

4.10 TERMINAL-NTSC SCHEMATIC DIAGRAM............................. 4-21

4.11 S-SUB SCHEMATIC DIAGRAM............................................... 4-23

4.12 DISPLAY, REC SAFETY/D.CASS SW AND

JACK SCHEMATIC DIAGRAMS .............................................. 4-25

4.13 D-PRE/REC SCHEMATIC DIAGRAM ...................................... 4-27

4.14 DIGITAL(HOST) SCHEMATIC DIAGRAM ................................ 4-29

4.15 DIGITAL(DMAIN) SCHEMATIC DIAGRAM .............................. 4-31

4.16 DIGITAL(D-VHS IF) SCHEMATIC DIAGRAM .......................... 4-33

4.17 DIGITAL(DVX) SCHEMATIC DIAGRAM ................................... 4-35

4.18 DIGITAL(VIDEO IF) SCHEMATIC DIAGRAM .......................... 4-37

4.19 DIGITAL(HD DEC) SCHEMATIC DIAGRAM ............................ 4-39

4.20 DIGITAL(LAPRAS) SCHEMATIC DIAGRAM............................ 4-41

4.21 DIGITAL(DSP) SCHEMATIC DIAGRAM .................................. 4-43

4.22 DIGITAL(AUDIO AD/DA) SCHEMATIC DIAGRAM ................... 4-45

4.23 DIGITAL(DECRIPTER) SCHEMATIC DIAGRAM ..................... 4-47

4.24 REGULATOR AND SUB REGULATOR CIRCUIT BOARDS .... 4-49

4.25 3D DIGITAL/4M AND S-SUB CIRCUIT BOARDS.................... 4-51

4.26 TERMINAL CIRCUIT BOARD .................................................. 4-52

4.27 DISPLAY, REC SAFETY AND JACK CIRCUIT BOARDS ........ 4-53

4.28 D-PRE/REC CIRCUIT BOARD ................................................ 4-55

4.29 DIGITAL CIRCUIT BOARD ...................................................... 4-57

4.30 MAIN CIRCUIT BOARD ........................................................... 4-61

4.31 VOLTAGE CHARTS .................................................................. 4-64

4.32 FDP GRID ASSIGNMENT AND ANODE CONNECTION ........ 4-65

4.33 REMOTE CONTROLLER SCHEMATIC DIAGRAM ................. 3-66

4.34 WAVEFORMS .......................................................................... 4-67

4.35 CPU PIN FUNCTION ............................................................... 4-68

4.36 SYSTEM CONTROL BLOCK DIAGRAM ................................. 4-69

4.37 AUDIO BLOCK DIAGRAM ....................................................... 4-71

4.38 VIDEO BLOCK DIAGRAM ....................................................... 4-73

4.39 D-VHS BLOCK DIAGRAM ....................................................... 4-77

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

SW.REG BOARD ASSEMBLY <01> ................................................ 5-6

SUB REG BOARD ASSEMBLY <02> .............................................. 5-7

MAIN BOARD ASSEMBLY <03> ..................................................... 5-8

3D DIGITAL/4M BOARD ASSEMBLY <05> ................................... 5-14

TERMINAL BOARD ASSEMBLY <06> .......................................... 5-16

A/C HEAD BOARD ASSEMBLY <12> ........................................... 5-16

S-SUB BOARD ASSEMBLY <15> ................................................. 5-16

DISPLAY BOARD ASSEMBLY <28> .............................................. 5-17

REC SAFETY BOARD ASSEMBLY <32> ...................................... 5-18

JACK BOARD ASSEMBLY <36> ................................................... 5-18

D-PRE/REC BOARD ASSEMBLY <43> ......................................... 5-18

DIGITAL BOARD ASSEMBLY <50> ............................................... 5-22

LOADING MOTOR BOARD ASSEMBLY <55> .............................. 5-32

4-5

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.

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

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

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.

S40888-01

SECTION 1

DISASSEMBLY

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 reverse order. Bend, route and dress the flat cables as they were originally laid.

[1]

[2]

[3]

[4]

[5]

[6]

[7]

Top cover, Bracket

Front panel assembly

SW.REG board assembly

Digital board assembly

D-PRE/REC board assembly

Drum assembly

Mechanism assembly

REC safety board assembly,

[8]

Display board assembly,

Jack board assembly

[9]

[10]

1.2

How to read the disassembly and assembly

Main board assembly

Bottom cover

Step/

Loc No.

[1] Top cover, D1

(1) (2) (3) (4) (5)

Part Name

Bracket 2(S1c)

Fig. No.

Point Note

4(S1a),(S1b),3(L1a), <Note 1a> 2(SD1a),(P1a),(W1a), CN1(WR1a),

1.3 Disassembly/assembly method

Step/

Loc No.

[1] Top cover, D1

[2] Front panel assembly D2 CN8201(WR2a), <Note 2a>

[3] SW.REG board D3 CN5302(WR3a), <Note 2a>

[4]

[5] D-PRE/REC board D5 (S5a), L5a(WR5a), <Note 2a>

[6] Drum assembly, D6 CON1(WR6a), <Note 2a>

[7] Mechanism assembly D7 CN1(WR7a), (S7a), <Note 2a>

[8] REC safety board D8 (S8a) <Note 2a>

[9] Main board assembly D9 2(S9a)

[10] Bottom cover, D10

Part Name

Bracket 2(S1d)

assembly CN5502(WR3b),

Digital board assembly

assembly Shield case(PRE), <Note 5a>

(Inertia plate), 4(L6a) (Roller arm assembly), (Cleaner assembly) (L6c)

assembly, Display board assembly,

Jack board assembly CN7191(WR8b)

(Foot(2)), 4(L10a) (Foot assembly) 4(L10b)

Fig. No.

D4 CN601(WR4a), <Note 2a>

Point Note

2(S1a), 2(S1b), (S1c)

-----------------

2(S2a), 4(L2a), 2(L2b), 3(L2c)

CN5504(WR3c), CN5303(WR3d), CN5503(WR3e), 2(S3a)

CN603(WR4b), <Note 4a> CN8803(WR4c), CN9801(WR4d), CN8002(WR4e), 2(S4a), (S4b), Earth plate

CN606(WR5b), CN3011

CN1(WR6b), <Note 6a> (S6a), (S6b), (S6c)

-----------------

(P6a), (L6b)

-----------------

(S7b), (S7c), (S7d), <Note 7a> S7e(WR7b), 2(L7a)

-----------------

CN7002(WR8a), <Note 8a> 4(L8a)

-----------------

-----------------

(S10a), 2(S10b), 4(L10c), 3(L10d)

(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:

•

The bracketed ( ) WR of the connector symbol are assigned nos. in priority order and do not correspond to those on the spare parts list.

(5) Adjustment information for installation

1-1

• Be careful not to damage the connector and wire etc. during connection and disconnection.

• When connecting the flat wire to the connector, be careful with the wire direction.

• When reattaching the Front panel assembly, make sure that the door opener “a” of the Cassette holder assembly is lowered in position prior to the reinstallation.

• When securing the screw (S4b), be sure to attach the earth plate together it.

• When securing the screw (S5a), be sure to connect the lug wire (WR5a) together it.

• When installing the drum assembly, secure the screws (S6a to S6c) in the order of a,b,c.

• When it is required to remove the screws (S7a to S7b) retaining the Mechanism assembly, please refer to the “Procedures 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 and switch 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.

• After removing the REC safety board assembly, remove the display board assembly.

(S1a)

(S1d)

[1] Top cover

(S1c)

(S1b)

(S1d)

[1] Bracket

Fig. D1

Procedures for Lowering the Cassette holder assembly

As the mechanism of this unit is integrated with the Housing assembly, the holder must be lowered and the two screws unscrewed when removing the Mechanism assembly.

(A)

Fig. 1

(B)

Fig. 2

Fig. 3

Turn the loading motor pulley in the direction as indicated by Fig.2. As both (A) and (B) levers are lodged twice, push the levers in the direction as indicated by Fig.3 to release them. When pushing the levers, do it in the order of (A), (B), (B), (A). When the holder has been lowered, turn the pulley until the cassette holder is securely in place without allowing any up/down movement.

(S2a)

(L2a)

(L2b)

(L2c)

[2] Front panel

assembly

(

WR2a

Detail C

)

CN8201

Detail B

(S2a)

(L2a)

Treatment of 1394 cable

Digital board assembly

Front panel assembly

Detail B

(L2b)

a <Note 2b>

Detail C

Display board assembly

1394 cable

Procedures for Lowering the Cassette holder assembly

1-2

Fig. D2

[3] SW. REG board assembly

CN5302

CN5504 CN5502

CN5503

CN5303

WR3a

(S3a)

WR3b

WR3e

(S3a)

WR3c

(S5a)

Shield case (PRE)

(L5a)

WR5a

[5] D-PRE/REC board assembly

WR5b

CN606

CN605

(CN3011)

Fig. D5

Note: When installing the Drum assembly, secure the screws (S6a to S6c) in the order of a, b, c.

Earth plate

CN8803

(S4a)

CN8002

CN9801

WR4d

Fig. D3

(S4b)

(WR4b)

(WR4a)

[4] Digital board assembly

WR4e

CN603

WR4c

CN601

(L6a)

Inertia plate

Roller arm assembly

[6] Drum assembly

Not used

Spacer

(P6a)

(L6b)

(S6a) <Note 6a>

(W6)

Not used

(S6c) <Note 6a>

CON1

Drum shield

(S6b)

WR6a <Note 2a>

(S6b) <Note 6a>

WR6b <Note 2a>

Cleaner assembly

(L6c)

Fig. D4

CN1

Fig. D6

1-3

Note: When installing the Mechanism assembly, secure the screws (S7a to S7b) in the order of a, b.

(S9a)

(S7b)

Q3003 End sensor <Note 7a>

(L7a) Spacer <Note 7a>

D3001 LED <Note 7a>

(S7d)

(S7a)

S3002 S cassette switch <Note 7a>

Fig. D7

CN1

WR7a <Note 2a>

(S7e)

WR7b <Note 7b>

(S7c)

[7] Mechanism assembly

[9] Main board assembly

(L7a) Spacer <Note 7a>

Q3002 Start sensor <Note 7a>

Fig. D9

(L8a)

WR8b <Note 2a>

CN7191

[8] Jack board assembly

(S8a)

[8] REC safety board assembly <Note 8a>

(L8a)

CN7002

WR8a <Note 2a>

[8] Display board assembly

Foot assembly

(L10b)

(L10c)

[10] Bottom cover

(L10d)

(L10b)

(L10a)

(S10b)

Foot(2)

(L10c)

(L10a)

(S10a)

1-4

Fig. D8

Fig. D10

1.4 Service position

This unit has been designed so that the Mechanism and Main board assemblies can be removed together from the chassis assembly. Before diagnosing or servicing the circuit boards, take out the major parts from the chassis assembly.

• In order to diagnose the playback or recording of the cassette tape, set the Mechanism assembly to the required mode before placing it upside down. If the mechanism mode is changed (including ejection) while it is in an upside down position the tape inside may be damaged.

1.4.1 How to set the “Service position”

(1) Refer to the disassembly procedure and perform the dis-

assembly of the major parts before removing the D-PRE/ REC board assembly.

(2) Remove the screws attaching the mechanism assembly

with the chassis assembly. Remove the screws attaching the board assembly, if necessary.

(3) Remove the combined Mechanism and Main board as-

semblies.

(4) Connect the wires and connectors of the major parts that

have been removed in step (1). (Refer to Fig.1-4-1a.)

(5) Place the combined Mechanism and Main board assem-

blies upside down.

(6) Insert the power cord plug into the power outlet and then

proceed with the diagnostics and servicing of the board assembly.

Notes:

• Before inserting the power cord plug into the power outlet, make sure that none of the electrical parts are able to short-circuit between the workbench and the board assembly.

• For the disassembly procedure of the major parts and details of the precautions to be taken, see “1.3 Disassembly/assembly method”.

• If there are wire connections from the Main board and Mechanism assemblies to the other major parts, be sure to remove them ( including wires connected to the major parts ) first before performing step (2).

• When carrying out diagnosis and repair of the Main board assembly in the “Service position”, be sure to ground both the Main board and Mechanism assemblies. If they are improperly grounded, there may be noise on the playback picture or FDP counter display may move even when the mechanism is kept in an inoperative status.

1.4.2 Precautions for cassette loading in the “Service position”

The REC safety board assembly detects cassette loading as well as cassette tabs. Therefore, after the assembly has been removed in the “Service position”, it is required to set the switch manually on the REC safety board assembly when a cassette is loaded.

1.4.3 Cassette loading and ejection methods in the “Service position”

(1) Insert a cassette halfway in the Cassette holder assem-

bly.

(2) Set the switch on the REC safety board assembly to on

(by pressing the switch).

(3) As soon as the cassette starts to be loaded, set the

switch on the REC safety board assembly to off (by releasing the switch).

(4) Now the desired operation (recording, playback, fast for-

ward, rewind, etc.) is possible in this status.

(5) The switch on the REC safety board assembly does not

have to be operated when ejecting a tape. But be sure to turn the set to the normal position before ejecting the tape.

Note:

•

In the “Service position”, the cassette tabs cannot be detected and recording becomes possible even with a cassette with broken tabs such as the alignment tape. Be very careful not to erase important tapes.

Digital board assembly

CN8002

CN9801

Main TP106 PB-FM TP2253 A.PB-FM TP4001 CTL.P TP7101 Y OUT

D-PRE/REC TP111 Video/STD/HS1 FF TP112 A/HS2 FF TP601 REC level 1 TP602 REC level 2 TP606 PB data 1 TP616 PB data 2

CN8803

CN8801 CN8802

To D-PRE/REC

CN603 CN601

To Digital

CN8002

CN9801

CN7191

Jack board assembly

To Digital

CN8803

CN7107

TP7101

CP6201

CN3009

TP7001

(MECHA1)

CN901

CN7104

TP616 TP112

TP602 TP601 TP606 TP111

VR6601 Separation

TP7002

(MECHA2)

Fig. 1-4-1a

S-Sub board assembly

TP106 TP4001 TP2253

CN601CN603

D-PRE/REC board assembly

REC Safety board assembly

CP4001

CP3002

Display board assembly

Terminal board assembly

3D Digital/4M board assembly

Main board assembly

VR1401 D/A level

CN5601

CN7005

CN7002

CN3008

To Digital

CN8801 CN8802

CN5302

CN5303

CN5504 CN5502 CN5503

Sub Reg board assembly

SW. Reg board assembly

1-5

1.5 Mechanism service mode

This model has a unique function to enter the mechanism into every operation mode without loading of any cassette tape. This function is called the “Mechanism service mode”.

1.5.1 How to set the “Mechanism service mode”

(1) Unplug the power cord plug from the power outlet. (2) Remove the front panel assembly. (3) Connect TP7001(MECHA 1) and TP7002(MECHA 2) on

the Display board assembly with a jump wire. (4) Insert the power cord plug into the power outlet. (5) With lock levers (A) (B) on the left and right of the Cas-

sette holder assembly pulled toward the front, slide the

holder in the same direction as the cassette insertion di-

rection. (For the positions of lock levers (A) (B), refer to

the “Procedures for lowering the Cassette holder assem-

bly” of 1.3 Disassembly/assembly method.) (6) The cassette holder lowers and, when the loading has

completed, the mechanism enters the desired mode.

1.6 Jig RCU mode

This unit uses the following two modes for receiving remote control codes.

1) User RCU mode : Ordinary mode for use by the user.

2) Jig RCU mode : Mode for use in production and serv-

icing.

When using the Jig RCU, it is required to set the VCR to the Jig RCU mode (the mode in which codes from the Jig RCU can be received). As both of the above two modes are stored in the EEPROM, it is required to set the VCR back to the User RCU mode each time that an adjustment is made or to check that the necessary operations have been completed. These modes can be set by the operations described below.

1.7 Opening on the chassis

The chassis of this VCR has openings for diagnosis of some parts on the board assembly.

Reel sensor (Supply)

TU6001

CN3011

Reel sensor (Take-up)

Rotary encoder

IC3001

Fig. 1-7-1a

1.6.1 Setting the Jig RCU mode

(1) Unplug the power cord plug from the power outlet. (2) Press and hold the “REC” and “PAUSE” buttons on the

VCR simultaneously, while plugging the power cord plug

into the power outlet.

When the VCR is set to the Jig RCU mode, the symbols

( “ : ” ) in the time display of the FDP are turned off.

1.6.2 Setting the User RCU mode

(1) Turn off the power. (2) Press the “REC” and “PAUSE” buttons of the VCR si-

multaneously. Alternatively, transmit the code “80” from

the Jig RCU.

1-6

1.8 Emergency display function

This unit has a function for storing the history of the past two emergencies (EMG) and displaying them on each FDP (or OSD). With the status of the VCR and mechanism at the moment an emergency occurred can also be confirmed.

FDP display model [FDP display]

0 : 00 : 00

E:** :**

*1 : *2 : 34

*5: *6 : *7

FDP (7segment LED) display model [FDP display]

0: 00

E: **

1: **

2: *1

3: *2

4: 34

5: *5

6: *6

7: *7

OSD display model [OSD display]

Normal display

EMG content display (E:Latest:Previous)

EMG detail information <1>

EMG detail information <2>

Normal display

EMG content display (Latest)

EMG content display (Previous)

EMG detail information <1> [Deck operation mode] EMG detail information <1> [Mechanism operation mode] EMG detail information <1> [Mechanism sensor information and Mechanism mode position] EMG detail information <2> [Type of the cassette tape in use <1>] EMG detail information <2> [Winding position of the cassette tape in use] EMG detail information <2> [Type of the cassette tape in use <2> (Winding area)]

EMG E: **:** *1 : *2 : 34

*5: *6 : *7

EMG content display (E:Latest:Previous)

EMG detail information <1> EMG detail information <2>

Notes:

•

The EMG detail information <1><2> show the information on the latest EMG. It becomes “ – – : – – : – –” when there is no latest EMG record.

•

When using the Jig RCU, it is required to set the VCR to the Jig RCU mode (the mode in which codes from the Jig RCU can be received).

Jig RCU

[Data transmitting method] Depress the “ ” ( 3 ) button after the data code is set.

CUSTOM CODE 43: A CODE 53: B CODE

DATA CODE

INITIAL MODE

Fig. 1-8a Jig RCU [PTU94023B]

1.8.1 Displaying the EMG information

(1) Transmit the code “59” from the Jig RCU.

The FDP shows the EMG content in the form of “E:**:**”.

<Example 1> E : 01 : 03

Previous EMG

Latest EMG

<Example 2> E : –– : ––

No EMG record

(2) Transmit the code “59” from the Jig RCU again.

The FDP shows the EMG detail information <1> in the form of “ * 1 : * 2 : 34 ”.

* 1 : Deck operation mode at the moment of EMG * 2 : Mechanism operation mode at the moment of EMG 3– : Mechanism sensor information at the moment of

EMG

–4 : Mechanism mode position at the moment of EMG

(3) Transmit the code “59” from the Jig RCU once again.

The FDP shows the EMG detail information <2> in the form of “ *5 : *6 : *7 ”.

* 5 : Type of the cassette tape in use <1> . * 6 : Winding position of the cassette tape in use * 7 : Type of the cassette tape in use <2> (Winding area)

(4) Transmit the code “59” from the Jig RCU once again to re-

set the display.

Notes:

•

For the OSD display model, all EMG information are showed by transmitting first code from the Jig RCU.

•

For the EMG content, see “1.8.3 EMG content description”.

•

For the EMG detail information <1> , see “1.8.4 EMG detail information <1> ”.

•

For the EMG detail information <2> , see “1.8.5 EMG detail information <2>”.

1.8.2 Clearing the EMG history

(1) Display the EMG history. (2) Transmit the code “36” from the Jig RCU. (3) Reset the EMG display.

(EMG-02e)

1-7

1.8.3 EMG content description

Note:

EMG contents “E08/E09” are for the model with Dynamic Drum (DD).

FDP CONTENT CAUSE

E01: Loading EMG

E02:

Unloading EMG

E03: Take Up Reel

Pulse EMG

E04: Drum FG

EMG

E05: Cassette Eject

EMG

E06: Capstan FG

EMG

E07: SW Power

Short-Circuit EMG

E08:

DD Initialized (Absolute Position Sensor) EMG

E09: DD FG EMG

E0A:Supply Reel

Pulse EMG

EC1 or EU1: Head clog warning

When the mechanism mode cannot be changed to another mode even when the loading motor has rotated for more than 4 seconds in the loading direction, [E:01] is identified and the power is turned off.

When the mechanism mode cannot be changed to another mode even when the loading motor has rotated for more than 4 seconds in the unloading direction, [E:02] is identified and the power is turned off.

When the take-up reel pulse has not been generated for more than 4 seconds in the capstan rotating mode, [E:03] is identified, the pinch rollers are turned off and stopped, and the power is turned off. However, the reel EMG is not detected in STILL/SLOW modes.

When the drum FG pulse has not been input for more than 3 seconds in the drum rotating mode, [E:04] is identified, the pinch rollers are turned off and stopped, and the power is turned off.

When the eject operation does not complete in 3 seconds after the start, [E:05] is identified, the pinch rollers are turned off and stopped, and the power is turned off. When the cassette insertion operation does not complete in 3 seconds after the start, the cassette is ejected. In addition, when the operation does not complete within 3 seconds after the start, [E:05] is also identified and the power is turned off immediately.

When the capstan FG pulse has not been generated for more than 1 second in the capstan rotating mode, [E:06] is identified, the pinch rollers are turned off and stopped, and the power is turned off.However, the capstan EMG is not detected in STILL/SLOW/FF/REW modes.

When short-circuiting of the SW power supply with GND has lasted for 0.5 second or more, [E:07] is identified, all the motors are stopped and the power is turned off.

When DD tilting does not complete in 4 seconds, [E:08] is identified, the tilt motor is stopped and the power is turned off.

When the DD FG pulse is not generated within 2.5 seconds, [E:09] is identified, the tilt motor is stopped and the power is turned off.

When the supply reel pulse has not been generated for more than 10 seconds in the capstan rotating mode, [E:0A] is identified and the cassette is ejected (but the power is not turned off). However, note that the reel EMG is not detected in the SLOW/STILL mode.

Presupposing the presence of the control pulse output in the PLAY mode, when the value obtained by mixing the two V.FM output channels (without regard to the A.FM output) has remained below a certain threshold level for more than 10 seconds, [E:C1] or [E:U1] is identified and recorded in the emergency history. During the period in which a head clog is detected, the FDP and OSD repeat the “3-second warning display” and “7-second noise picture display” alternately.

EMG code : “E:C1” or “E:U1” / FDP : “U:01” / OSD : “Try cleaning tape.” or “Use cleaning cassette.” The head clog warning is reset when the above-mentioned threshold has been exceeded for more than 2 seconds or the mode is changed to another mode than PLAY.

The mechanism is locked in the middle of mode transition.

. The mechanism is locked at the loading end due to the encoder position

reading error during mode transition.

Power is not supplied to the loading MDA.

The mechanism is locked in the middle of mode transition.

The mechanism is locked at the unloading end due to the encoder position reading error during mode transition.

Power is not supplied to the loading MDA.

The take-up reel pulse is not generated in the FWD transport modes (PLAY/ FWD SEARCH/FF, etc.) because;

1) The idler gear is not meshed with the take-up reel gear;

The idler gear is meshed with the take-up reel gear, but incapable of wind-

ing due to too large mechanical load (abnormal tension);

3) The take-up reel sensor does not output the FG pulse.

The supply reel pulse is not generated in the REV transport modes (REV SEARCH/REW, etc.) because;

1) The idler gear is not meshed with the supply reel gear.

2) The idler gear is meshed with the supply reel gear, but incapable of winding due to too large a mechanical load (abnormal tension);

3) The supply reel sensor does not output the FG pulse.

Power is not supplied to the reel sensors.

The drum could not start or the drum rotation has stopped due to too large a load on the tape, because;

1) The tape tension is abnormally high;

The tape is damaged or a foreign object (grease, etc.) adheres to the tape.

The drum FG pulse did not reach the System controller CPU because;

1) The signal circuit is disconnected in the middle;

2) The FG pulse generator (hall device) of the drum is faulty.

The drum control voltage (DRUM CTL V) is not supplied to the MDA.

Power is not supplied to the drum MDA.

The cassette cannot be ejected due to a failure in the drive mechanism of the housing.

When the housing load increases during ejection, the loading motor is stopped because of lack of headroom in its drive torque.

Housing load increasing factors: Temperature environment (low temperature, etc.), mechanism wear or failure.

The sensor/switch for detecting the end of ejection are not functioning normally.

The loading motor drive voltage is lower than specified or power is not supplied to the motor (MDA).

When the user attempted to eject a cassette, a foreign object (or perhaps the user's hand) was caught in the opening of the housing.

The capstan could not start or the capstan rotation has stopped due to too large a load on the tape, because;

1) The tape tension is abnormally high (mechanical lock);

2) The tape is damaged or a foreign object (grease, etc.) is adhered to the

tape (occurrence of tape entangling, etc.).

The capstan FG pulse did not reach the System controller CPU because;

1) The signal circuit is disconnected in the middle;

2) The FG pulse generator (MR device) of the capstans is faulty.

The capstan control voltage (CAPSTAN CTL V) is not supplied to the MDA.

Power is not supplied to the capstan MDA.

The SW 5 V power supply circuit is shorted with GND.

The SW 12 V power supply circuit is shorted with GND.

1. The absolute value sensor is defective. (The soldered parts have separated.)

2. The pull-up resistor at the absolute sensor output is defective. (The soldered parts have separated.)

3. Contact failure or soldering failure of the pins of the connector (board-to-board) to the absolute value sensor.

The absolute value sensor data is not sent to the System Controller CPU.

1. The FG sensor is defective. (The soldered parts have separated.)

2. The pull-up resistor at the FG sensor output is defective. (The soldered parts have separated.)

3. Contact failure or soldering failure of the pins of the connector (board-to-board) to the FG sensor.

4. The power to the sensor is not supplied. (Connection failure/soldering failure)

5. The FG pulse is not sent to the System Controller CPU.

The tilt motor is defective. (The soldered parts have separated.)

7. The drive power to the tilt motor is not supplied. (Connection failure/soldering failure)

8. The tilt motor drive MDA - IC is defective.

9. Auto-recovery of the DD tilting cannot take place due to overrun.

The supply reel pulse is not generated in the FWD transport mode (PLAY/ FWD SEARCH/FF, etc.) because;

1) PLAY/FWD or SEARCH/FF is started while the tape in the inserted cas-

sette is cut in the middle;

2) A mechanical factor caused tape slack inside and outside the supply

reel side of the cassette shell. In this case, the supply reel will not rotate until the tape slack is removed by the FWD transport, so the pulse is not generated until then;

3) The FG pulse output from the supply reel sensor is absent.

The take-up reel pulse is not generated in the REV transport mode (REV SEARCH/REW, etc.).

1) REV SEARCH/REW is started when the tape in the inserted cassette

has been cut in the middle;

2) A mechanical factor caused tape slack inside and outside the take-up

reel side of the cassette shell. In this case, the supply reel will not rotate until the tape slack is removed by the REV transport, so the pulse will not be generated until that time;

3) The FG pulse output from the take-up reel sensor is absent.

The power to a reel sensor is not supplied.

1-8

Table 1-8-3a

+ 28 hidden pages

JVC HM-DH3000 Service Manual

TABLE OF CONTENTS

Important Safety Precautions

DISASSEMBLY

1.1 Disassembly flow chart

How to read the disassembly and assembly

1.3 Disassembly/assembly method

1.4 Service position

1.5 Mechanism service mode

1.6 Jig RCU mode

1.7 Opening on the chassis

1.8 Emergency display function