Panasonic NV-SJ420EG User manual

ORDERNO. VRD0103012C2
Video Cassette Recorder
NV-SJ420EG / NV-SJ420EGM / NV-SJ420EGN / NV-
SJ420EGY / NV-SJ420B
Z-MECHANISM
SPECIFICATIONS
2001 Matsushita ElectricIndustrial Co., Ltd. All rights reserved.
Unauthorized copying and distribution isaviolation of law.
1

1. INTRODUCTION
This service manual contains technical information whichwill allowservice personnel to
understand and service this model.
If the circuit is changedormodified, this information will be followedbysupplementaryservice
manual tobe filedwithoriginal service manual.
Note:
1. Adjustment procedures, DisassemblyProcedures and Assembly
Procedures for Mechanism Chassisare separate volume from this
service manual. / Please refer to the service manual for Z-
Mechanism Chassis. (Order No. VRD9802005C2)
2. The Model No. isindicated on the SchematicDiagram and Circuit
Board Diagrams as follows.
Model No. Indication Mark
NV-SJ420EG/EGM/EGN (A)
NV-SJ420EGY (B)
NV-SJ420B (C)
2. GENERAL DESCRIPTIONS
2.1. SERVICECAUTION
2.1.1. REPLACING IC7702/EEPROM
Whenthe EEPROM: IC7702 is replaced, applicable model code, option code and electrical
adjustment data will not be available.
Therefore, enterand/oradjust the necessarydata afterreplacing IC7702 byreferring following
procedure.
STEP1.REPLACE THE IC7702
1. Remove the C.B.A. with Mechanism unitbyreferring the
Disassemblyprocedure.
2. Disconnect the AC plug and replace the IC7702.
2

STEP2.INPUTTHE MODEL& OPTION CODE
1. Set up the applicablemodel code and option code byordering the
following table.
PROCEDURE F.I.P. DISPLAY
Turnon the Service Mode
1.Press the FF keyand the
EJECTkeysimultaneouslyfor
more than3 seconds.
Activate the Service Mode 2
2.While keepplacing FF key,
press the EJECTkeyintwice.
Activate the Entering Mode.
3.Press the EJECTkeyformore
than3 seconds.
Set the Mode 2.
4.Press the CH UP keyintwice.
Displaythe Setting Code.
5.Press the POWER Button to
turnthe poweron.
(Colon starts
flashing)
Enterthe Model and Option Code.
6.Set the applicable Model and Option code by
using REW, PLAY, STOP and FF keys on the
Remote Controller. (See Fig.S1 & S2)
Exit fromService Mode.
7.Press the POWER Button to
turnthe poweroff.
8. Press FF and EJECTkeys
simultaneouslyin6 times.
(Normal
Indication)
Fig.S1 Service Secreen(sample)
3

Model No. Model
Code Option Code 1 Option Code 2 Option Code 3
NV-
SJ420EG/ /
EGM/EGN/
EGY
33 / (21h) 8 / (08h) 244 /
(F4h) 6 / (06h)
NV-SJ420B 35 / (23h) 40 / (28h) 244 /
(F4h) 5 / (05h)
Fig. S2 Model Code & Option Code
NOTE:
Since all electrical adjustments data is still not available, perform the Electrical Adjustment
continuously.
2.1.2. CYLINDER UNITREPLACEMENT
1. CYLINDERUNITREPLACEMENT
A. Remove the mechanism unitfrom MAINC.B.A./Chassisby
referring “SECTION2. DisassemblyProcedure”.
B. Remove the 3screws(A)of the CYLINDERUNITwith ascrew
driver.
C. Unlock the 4locking tabs (B)and disconnect the Cylinder
fiexiblecard from the FPCHolder.
D. Remove the CYLINDERUNIT.
CAUTION:
Handlethe Cylinder fiexiblecard with care. When itdamaged, you
shouldreplace wholeCylinder unit.
Fig. S3
4

2. UPPERCYLINDERDISASSEMBLY
A. Remove 2screws(A).
B. Remove the Cylinder Stator Unit.
C. Remove 2screws(B).
D. Remove the Cylinder Rotor Unit.
E. Loose Hex screw (C)(1.5mm) and remove the CYLINDER
RETAINER.
F. Remove the Upper Cylinder. Fig. S4
5

3. UPPERCYLINDERASSEMBLY
When reassembling, perform the steps inthe reverse order.
Notes:
1. Install the Cylinder Retainer so that the 2holes on top of the
Cylinder Retainer are at right angles with the P3502 Connection.
2. Tighten the Hex screw (C)(1.5mm) whilepressing downon top of
the Cylinder Retainer. Fig. S5
6

3. Install the Cylinder Rotor Unitso that the inner holeof the
Cylinder Rotor Unitfits to the small projection (D)on top of the
Upper Cylinder.
4. Tighten 2screws(B). Fig. S6
5. install the Cylinder Stator Unit.
6. Tighten 2screws(A). Fig. S7
7. Confirm the PG SHIFTERADJUSTMENTwith the alignment tape
7

(PAL: VFJ8125H3F) and adjust itifnecessary.
2.1.3. CHECKING OFMAIN C.B.A.
Whenservicing the MAIN C.B.A., take out the MAIN C.B.A. and mechanismfromthe frame and
turnover.
Fig. S8
2.1.4. FLATCARD CABLE INSTALLATION
Wheninstalling the Flat CardCable on the connector, install the Flat CardCable withthe cable
contacts facing the connectorcontacts.
Fig. S9
2.2. REMOVALOFCASSETTE TAPE
There are 2 ways toremove a cassette tape.
1. Service Information DisplayOperation
A. Press the FF and EJECTkeyssimultaneoslyfor 3seconds and
set the Service Mode 7.
B. Press STOPkeyinorder to rotate the Loading Motor for
unloading operation. (Payan attention of tape slack)
2. Manual Operation
A. Disconnect the AC Mains Lead and remove the Top Panel.
B. Rotate the MainCam Gear clockwise until the Loading Posts
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move to fullyunloaded position as shownin Fig. S10 . (Tape is
remaining) Fig. S10
C. Rotate the Capstan Motor clockwise from the bottom side to
take up the tape. Fig. S11
D. Rotate the MainCam Gear clockwise until the cassette tape is
ejected.
2.3. INTRODUCTIONOFVIDEO HEAD CLEANING CASSETTE /
(POLISHING TYPE)
1. We are pleased to introduce PanasonicVideo Head Cleaning
Cassette, VFK0923FT [for service purposes] and VFK0923FSE [
for end users] for all VHS/SVHSVCPand VCR.
2. These cleaning cassettes are exclusive removing the hard and
stickyclogging on video heads.
3. These improve the efficiencyof video head cleaning service and
shortening cleaning time for end users.
9

VFK0923FT
(ForService usage)
Type of Cassette Full VHS Cassette
Cleaning Time 10 Seconds/Time
Tape Length 20 m
Usabilityina Path 180 Times
VFK0823FSE
(Forend users)
Type of Cassette Full VHS Cassette
Cleaning Time 10 Seconds/Time
Tape Length 3.34 m
Usabilityina Path 30 Times
10

VFK0823FSE
(Forend users)
Note:
The tape material itselfisthe same inboth types.
2.4. SELF-DIAGNOSISRESULT DISPLAY
The "SELF-DIAGNOSIS RESULT DISPLAY & MEMORY function is built inthis VTR.
It means that whenthe VCR detects undesirable condition, it canbe displayeda “Errorcode
(Twonumbers fromthe left)” withService Mode 2.
Since the "Errorcode" is storedinthe EEPROM, it canbe displayedalthough after
disconnectedthe AC leads. It canbe displayedwithService Mode 2.
(If a second errorhadbeendetected, onlythe most recent erroris displayed. )
Formore details, refertothe Service Manual forZ-MechanismChassis Ordernumber
VRD9612M129.
11

INDICATION CAUSE REMEDY/CHECK
01 Aftercylinderlock is detected, the cylinder
does not start rotating againevenaftertape
unloading.
Check the cylindermotordrive
circuit.
02 Cassette tape is not wound up during the tape
unloading except EJECTmode. Check the capstanmotordrive
circuit.
03 Mechanismlocks during mode transition
except EJECTmode.
1. Check theloading motor drivecircuit.
2. Check themechanism phase alignment.
3. Check themodeswitch.
04 Mechanismlocks during tape unloading. 1. Check theloading motor drivecircuit.
2. Check themechanism phase alignment.
06 Mechanismlocks aftertape unloading in
EJECTmode.
1. Check theloading motor drivecircuit.
2. Check themechanism phase alignmentfor
cassette
07 During recording mode, recording signal is
less thanthe normal condition. Protection of the over-current
flowing
transistorwhichproduces the
power
forrecording mode.
08 Recording circuit works except recording
mode. Check the recording circuit.
16 Cylinderlock detection. Check the cylinderunit and the
cylinder
drive circuit.
17 Supplyreel mechanismlock detection Check the supplyreel mechanism
and
supplyreel circuit.
18 Take-up reel mechanismlock detection Check the Take-up reel mechanism
and
Take-up reel circuit.
2* PG shifterautomatic adjustment error. Check the servo/systemcontrol
circuit
cylinderunit.
Fig. T1 Self-Test indication Display
2.5. CAUTIONFORAC MAINSLEAD (NV-SJ420B)
3. ADJUSTMENT PROCEDURES
3.1. DISASSEMBLY METHOD
3.1.1. DISASSEMBLY FLOW CHART
This flowchart indicates disassemblysteps of the cabinet parts and the circuit boards inorder
tofind the necessaryitems forservicing.
Whenreassembling, perform the steps inthe reverse order.
Fig. D1
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3.1.2. DETAILOFDISASSEMBLY METHOD
1. REMOVALOFTHETOPPANEL
Remove 4 Screws (A)
Fig.D2
2. REMOVALOFTHEFRONTPANEL UNIT
Unlock 7 Tabs (B)
Fig. D3
13

3. REMOVALOFTHEMECHANISM UNIT
Remove Screw(C)
Remove CYLINDER SHIELD
PLATE
Remove Screw(D)
Remove 3 Screws (E)
Remove 2 Screw(F)
Note:
1. Keep pressing 2stoppers on Cassette Holder Plate and Press
Cassette Holder Plate to the rear.
2. Remove the Mechanism Unitafter bend the Cylinder Shieldinthe
direction of the arrow.
Fig. D4
14

4. REMOVALOFTHEMAINC.B.A.
Remove 4 screws (G)
Unlock 4 Tabs (H)
Fig. D5
NOTE:
Before mounting the MAIN C.B.A. ontothe frame, be sure toconfirm that the insulation sheet is
mountedon the frame as shownin Fig. D6 .
15

Fig. D6
5. SERVICING POSITION Fig. D7
3.2. MECHANICALADJUSTMENTPROCEDURES
Refertothe Service Manual forZ-MechanismChassis. / (OrderNo. VRD9802005C2)
3.3. ELECTRICALADJUSTMENTPROCEDURES
3.3.1. TESTEQUIPMENT
The following equipments are requiredforElectrical Adjustments.
1. Dual-Trace Oscilloscope
-Voltage Range: 0.005-5V/div
-FrequencyRange: DC-35MHz
-Probes: 10:1 / 1:1
2. FrequencyCounter
-FrequencyRange: 0-10MHz
-Probes: 1:1
3. Universal Counter
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4. Digital VoltMeter (D.V.M.)
5. Video Sweep Generator
6. Sinewave Generator
7. Video Pattern Generator
8. Monitor TV
9. DC Power Supply
10. VHSBlank Tape
11. VHSAlignment Tape
-Parts No.:VFJ8125H3F(PAL)
3.3.2. VCR SETTING
Whenno indication inthe procedure, set eachselectoras follows.
1. TAPE SPEED:SP
2. CHANNEL: AV1/AV2/AV3
(Set to signal input terminal number)
3.3.3. ADJUSTMENTS
ITEM TP ADJ. MODE INPUT TAPE M. EQ. SPEC.
REMARKS
PG SHIFTER
/
ADJUSTMENT
--- --- PLAYBACK--- ALIGNMENT
TAPE /
(PAL)
--- --- Referto
procedure
PG
SHIFTER
ADJUSTMENT
shownin
Fig.E3.
AI FUNCTION
/
ADJUSTMENT
--- --- PLAYBACK
/ (SELF-
REC)
PAL/
COLOUR
/ BAR
BLANK /
TAPE --- --- Referto
the
procedure
of
FUNCTION
ADJUSTMENT
shownin
Fig.E4.
17

ITEM TP ADJ. MODE INPUT TAPE M. EQ. SPEC.
REMARKS
VIDEO /
FREQUENCY
/ RESPONSE
/
ADJUSTMENT
VIDEO
OUT --- SP/LP/EP /
PLAYBACK
/ (SELF-
REC)
VIDEO /
SWEEP
/ (See
Fig.E1)
BLANK
TAPE OSCILLO /
SCOPE/ /
VIDEO
SWEEP
GENERATOR
SP: 0+-1
(dB)
(90~110%)
LP: 0+-1
(dB)
(90~110%)
EP: 0+-3
(dB)
(70~140%)
[LP/EP
MODE:
B/BL
ONLY]
(SeeFig.
E2)
Referto
the
procedure
of
FREQUENCY
RESPONSE
ADJUSTMENT
shownin
Fig.
Fig.E1 Fig.E2
CONDITION: BURSTSIGNALOFF /
75 ohmTERMINATED
3.3.4. PG SHIFTER ADJUSTMENT/ (AUTOMATIC)
18

PROCEDURES FIP DISPLAY
Press the FF and EJECTKeys
simultaneouslyfor3 seconds.
Press the FF and EJECTKeys
simultaneouslytwice.
Press the EJECTkeyfor3
seconds.
Press the CH UP keyonce.
Insert the Alignment cassette
tape. (PAL:VFJ8125H3F)
Whenthe sequence of the automatical adjustment
has beenterminated, the following action has
beenmade.
*SUCCEED: The cassette tape is ejected.
*ERROR : The "F2"is displayedon the FIP.
(Check the Servo/Syscon circuit and
Cylinderunit.)
Release the Service mode bypressing the EJECT
and FF keys simultaneouslyin6 times until the FIP
becomes normal indication.
Fig. E3
3.3.5. AI FUNCTION ADJUSTMENT(AUTOMATIC)
19

PROCEDURES FIP DISPLAY
Press the FF and EJECTKeys
simultaneouslyfor3 seconds.
Press the FF and EJECTKeys
simultaneouslytwice.
Press the EJECTkeyfor3
seconds.
Press the CH UP keyin3 times.
Insert the blank cassette tape.
(The adjustment is
automaticallystarted.)
Whenthe sequence of the automatical adjustment
has beenterminatedsuccessfully, the VCR goes to
STOP mode.
Release the Service mode bypressing the EJECT
and FF keys simultaneouslyin6 times until the FIP
becomes normal indication.
Fig. E4
3.3.6. VIDEO FREQUENCY RESPONSE ADJUSTMENT
PROCEDURES FIP DISPLAY
Input the Videosweepsignal.
(See Fig.E1)
Press the FF and EJECTKeys
simultaneouslyfor3 seconds.
Press the FF and EJECTKeys
simultaneouslytwice.
Press the EJECTkeyfor3
seconds.
Press the CH UP and/orCH
DOWN keyuntil "11" is
displayedon FIP.
Insert the Self-recordedtape
and playback it. (SP/LP/EP
mode)
20