Specific Service Instructions - JVC HR-J4020UA Service Manual

2.1 Different table of features
The following table indicates main different points between models HR-J4020UA, HR-J7020UA, HR-J4020UB and HR-J7020UM.
POWER PLUG
HiFi HEAD
SHUTTLE SEARCH
(LATCH)-PAL
VIDEO SYSTEM
SQPB
RECORDING &
PLAYBACK SPEED
REAR AV INPUT TERMINAL
STEREO DECODER
RF OUT CH/RF OUT SYSTEM [INITIAL]
CLOCK / SUMMER TIME ADJ.
→
AUTO SP EP(LP) TIMER
DISPLAY TYPE
POWER OFF DIMMER
OSD LANGUAGES
DISPLAY OFF
NOTE:
Mark ← is same as left.
2.2 Service position
This unit has been designed so that the Mechanism and Main
board assemblies can be removed together from the chassis as-
sembly. Before diagnosing or servicing the circuit boards, take
out the major parts from the chassis assembly.
2.2.1 How to set the "Service position"
(1) Refer to the disassembly procedure and perform the disas-
sembly of the major parts before removing the Mechanism
assembly.
(2) Remove the screws that fix the Mechanism assembly to
the Chassis assembly. If any other screws are used to fix
the boards, remove them also.
(3) Remove the combined Mechanism and Main board assem-
blies.
(4) If any other major parts are used, remove them also.
(5) Connect the wires and connectors of the major parts that
have been removed in steps (1) to (4). (Refer to Fig. 2-2a.)
(6) Place the combined Mechanism, Main board and other
board assemblies upside down.
(7) Insert the power cord plug into the power outlet and then
proceed with the diagnostics and servicing of the board as-
sembly.
Note:
• Before inserting the power cord plug into the power out-
let, make sure that none of the electrical parts are able
to short-circuit between the workbench and the board
assembly.
SECTION 2

SPECIFIC SERVICE INSTRUCTIONS

HR-J4020UA
IRAM
NOT USED
× ×
SP 7, LP 7
PAL-N (SP,LP) /
NTSC (SP,EP)
NTSC (SP,EP)
NTSC:REC:SP/EP,
PLAY:SP/LP/EP
PAL-N:REC:SP/LP,
PLAY:SP/LP
USED
NOT USED
[3CH],4CH,OFF/[N]
24H / USED(MANUAL)
→
SP LP
4-DOT LED
NOT USED
SPANISH, ENGLISH
NOT USED USED(with MENU)
HR-J7020UA HR-J4020UB
←
BRAZIL PLUG
USED NOT USED
←
NOT USED
PAL-M/NTSC (SP,EP)
→
NTSC
←
(SP,EP)
→
PAL PAL-M PB(SP,LP)
←
PAL-M/NTSC (SP,EP)
REC:SP/EP,
←
PLAY:SP/LP/EP
←
MTS NOT USED
←
[3CH],4CH,OFF/[M]
←
←
SP
4-DIGIT LED 4-DOT LED
USED NOT USED
←
PORTUGUESE
NOT USED
• For the disassembly procedure of the major parts and
details of the precautions to be taken, see "3.1 Remov-
ing the major parts".
• 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 assem-
blies. 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 inop-
erative status.
• In order to diagnose the playback or recording of the cas-
sette 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 up-
side down position the tape inside may be damaged.
• For some models, the mechanism and board assem-
blies are attached by connectors only. When carrying
out a diagnosis or repair of the boards in the "Service
position", make sure that the connectors are not dis-
connected.
HR-J7020UM
SASO
USED
←
PAL-M PB
NTSC (SP,EP)
NTSC (SP,EP)
←
←
NOT USED
MTS
←
←
12H / NOT USED
→ ←
EP
4-DIGIT LED
USED
SPANISH, ENGLISH
USED(with MENU)
(No.YD007)1-5