Panasonic NV-MV21GC User manual

ORDERNO. MAV0404004C8
Video Cassette Recorder
NV-MV21GN / NV-MV21GC / NV-MV21GCS / NV-MV21GCSX /
NV-MV21EE / NV-MV21GCU / NV-MV21GH
R4-MECHANISM
SPECIFICATIONS
1

2004 Matsushita ElectricIndustrial Co., Ltd. All rights reserved.
Unauthorized copying and distribution isaviolation of law.
1. INTRODUCTION
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.
2

Please refer to the service manual for R4-Mechanism Chassis.
(Order No. VRD0202010C8)
2. The Model No. isindicated on the SchematicDiagram and Circuit
Board Diagrams as follows.
Model No. Indication Mark
NV-MV21GN (A)
NV-MV21GC/GCS/GCSX (B)
NV-MV21EE (C)
NV-MV21GCU (D)
NV-MV21GH (E)
1.2. ABOUTLEAD FREE SOLDER(PbF)
Distinction of PbF PCB:
PCBs (manufactured) using leadfree solderwill have a PbF stampon the PCB.
Caution:
-Pb free solder has ahigher melting point than standard solder,
Typicallythe melting point is50-70°F (30-40°C)higher. Please use
ahigh temperature soldering iron. Incase of soldering iron with
temperature control,please set itto 700±20°F (370±10°C)
-Pb free solder will tend to splash when heated too high (about
1100°F/600°C).
Whensoldering orunsoldering, please completelyremove all of the solderon the pins orsolder
area, and be sure toheat the soldering points withthe Pbfree solderuntil it melts enough.
2. GENERAL DESCRIPTIONS
2.1. SERVICECAUTION-1
Whenthe MicroprocessorIC6001 and/orBack-up batteryB7751 are replaced, readthe following
procedure carefullyand proceedit.
[REASONS]
There is a RAM inthe IC6001, whichis backing up:
1. Programme Navigation Data [See NOTE1]
2. TV Tuning Data
3. PG Shifter Adjustment Data
4. Option Setting Data
3

WhenIC6001 are replaced, all above listeddata become not available.
These data is backedup byusing the powersource of:
*AC Connected: AC Powersource
*AC Disconnected: Back-up Battery(B7751) & Back-up Capacitor(C7752)
[NOTE1]
As foryourreference, without inserting a tape intoa VCR, you canconfirm that the NAVI data
that is back up withIC6001 as showninthe following steps.
1. Indicate the "NAVI"mark on the Front Information Panel. (Press
the Menu button and select the option, then set the "NAVI"to ON
mode.)
2. Turn on the Service Mode and press the "NAVI"button on the
Remote Controller inmore than 5seconds. The "NAVI"data list is
displayed on the Monitor. (Press the "MENU"button on the
Remote Controller for cancellation.)
Although storedNAVI data canbe confirmedon the monitor, there is no waytotransferthe
NAVI data toIC6001whichis newlymounted.
2.1.1. REPLACING PROCEDURE [IC6001]
[1.PREPARATION]
Before replacing IC6001:
1. Take note that stored TV broadcast channels. (Because, its user
maystore TV broadcasts bymanuallyother than "Auto Tuning"
operation and itisalso erased.)
NOTE:
During servicing, do not make a short circuit betweenIC6001-pin37 (5V) withotherline/
Components otherwise IC6001 maybe broken.
CAUTION:
*When replacing the B7751, be sure to read/follow the "HOWTO
REPLACETHELITHIUMBATTERY" section.
[2.REPLACING PROCEDURE IN STEPS]
STEP1.PREPARATION
1. Disconnect the AC plug before removing the C.B.A. with
4

Mechanism unitbyreferring to the Disassemblyprocedure.
STEP2.REPLACE THE IC6001
1. Replace the IC6001. (Donot make ashort circuitbetween IC6001-
pin37 and other pins/Components.)
STEP3.RESETTHE IC6001 ATONCE
1. Connect the AC plug.
2. Connect ajumper wire between TL7510 (RESET) and TL7509
(GND)for asecond to reset the Microprocessor IC6001.
Note:
Since the resistance at pin2 as well as pin3 of IC6001 decides the model distinction data, there
is no needtoset up the Model code, whichis necessaryinthe previous models.
STEP4.LINE-IN SETTING & ACTIVATE PLUG-IN A.T.P.
1. Press the Channel up and downkeyssimultaneouslyfor more
than 3seconds, under the condition of the no tape isinthe unit.
2. Confirm that "A1" and "A2" can be displayed on the FIPby
pressing the CH UPand CH DOWNbuttons.
NOTE:
If "DIRECTREC" on the OPTION setting screenis set to[ON], the input signal is fixedto"A1",
and the Channel up and downkeys are not effective.
3. Disconnect the AC plug for few seconds and connect itagain, and
press POWERbutton for turning the power to on from off to carry
5

out the "Plug inAuto Tuner Preset".
4. Since other than the channelsthat can be stored by"Auto
Tuning" operation are not availableyet, preset manuallyby
consulting the note of its availableTV channelsof which you took
before.
NOTE:
The Factoryshipping condition of OSD setting is not restoredbyabove operation.
5. Change the OSDsetting to the Factoryshipping condition if
necessary, byreferring to Option Setting on the Operating
Instructions as showninthe following chart.
STEP5.TAPE INTERCHANGEABILITY ADJUSTMENT
Refertothe Electrical Adjustment Procedures.
2.2. CAUTIONFORAC MAINSLEAD (NV-MV21GC/ GH)
2.3. HOWTO REPLACETHELITHIUMBATTERY
2.3.1. GENERALDESCRIPTION
There is a RAM inthe IC6001, whichis backing up the following data byusing the powersource
of B7751 (Back-up Battery) and C7752 (Back-up Capacitor: Back-up time is approximately30
minutes).
1. Programme Navigation Data
2. TV Tuning Data
3. PG Shifter Adjustment Data
6

4. Option Setting Data
2.3.2. REPLACEMENTPROCEDURE
NOTE:
This work shouldbe finishedwithin30 minutes sothat the RAM data wouldnot be lost as
running out of current fromthe Back-up CapacitorC7752.
1. Remove the Top Panel and Mechanism unitwith MainC.B.Aby
referring to the Disassembling Procedure.
2. Unsolder the Lithium Battery:B7751 and then replace itwith a
new one (See Fig. B1).
Fig. B1
NOTE:
The lithiumbatteryis a critical component (ManufacturedbyPanasonic.)
It must neverbe subjectedtoexcessive heat ordischarge.
It must therefore onlybe fittedinequipment designedspecificallyforits use.
Replacement batteries must be of the same type and manufacture.
Theymust be fittedinthe same mannerand location as the original battery, withthe correct
polaritycontacts observed.
Donot attempt tore-charge the batteryorre-use it foranyotherpurpose.
It shouldbe disposedof inwaste products destinedforburial ratherthanincineration.
7

2.4. SERVICECAUTION-2
2.4.1. CAUTION FOR AUTO TUNING
PROCEDURE
AutoTuning will start bythe following procedure.
1. Connect the DIN-RFCable.
2. Connect the AC Mains Lead.
3. Turn on the VCR.
Auto Tuning will start.
Auto Tuning search for TV stations from VHSminimum to UHF
maximum and memorizes everytuned program position. Other
program positions are skipped.
Auto Tuning takes five or more minutes to complete its search.
Donot touch the VCR during Auto Tuning.
Auto Tuning will stop halfway, ifthe VCR isoperated or the aerial
lead and/or the mains lead are disconnected.
Incase the VCR stopped during Auto Tuning, the VCR has to be
reset and restarted. See the following item 2.
8

NOTE:
1. Ifthe VCR isturned on with the antenna not connected, all
channelsare skipped. Therefore, firmlyconnect the antenna and
then turn the VCR off and on againto execute Auto tuning.
2. When Auto Tuning iscanceled halfway, Auto Tuning isnot
execute even ifthe VCR isturned off and then turned on again,
Inthiscase, Auto Tuning has to be restarted bythe following
procedures.
A. Press EJECTand remove the Videocassette.
B. Keep UPand DOWNon the VCR pressed simultaneouslyfor 3
seconds or more during the VCR on.
The channel displayed on the VCR displaydisappears for
moment then changes to 2.
C. Turn off the VCR and then turn iton. Auto Tuning commences.
3. Ifyou turn the VCR off during Auto Tuning, Auto Tuning will stop
halfway.
The VCR shouldbe reset and restarted bythe item 2inorder to
execute Auto Tuning.
4. Ifthe VCR starts playback during Auto Tuning, Auto Tuning will
stop halfway.
The VCR shouldbe reset and restarted bythe item 2inorder to
execute Auto Tuning.
5. To cancel Auto Tuning Mid-operation, press POWERDuring Auto
Tuning (The VCR isturned off).
6. When the VCR ismoved to the other area or country, TV
broadcasts shouldbe stored again.
2.4.2. CHECKING OFMAIN C.B.A.
Whenservicing the MAIN C.B.A., take out the MAIN C.B.A. and mechanismfromthe frame. Turn
the MAIN C.B.A. overas shownin Fig. S1.
Fig. S1
9

2.4.3. REMOVALOFCASSETTE TAPE
Whenthe cassette tape couldnot be uninstalledfromanelectrical malfunction, There are 2
ways toremove a cassette tape.
1. Removal bycompulsoryunloading.
A. Press FF and EJECTbutton simultaneouslyfor more than 3
seconds and set the Service Mode to 7.
B. Press STOPbutton inorder to unload the mechanism. (Pay
attention to tape slack)
Service Mode Indication:
7** ** (STOP) 70L ** (EJECT)
2. Removal bymanual operation byrotating the Loading Motor with
the batteries.
A. Disconnect the AC plug, and remove the Top Panel and the
Front Panel byreferring to the DisassemblyProcedures.
B. Connect three batteries (1.5V spec.)to the Loading Motor in
series for supplying 4.5V to rotate the Loading Motor as shown
in Fig. S2.Fig. S2
10