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2.4 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.
2.4.1 How to set the "Service position"
(1) Refer to the disassembly procedure and perform the disas-
sembly of the major parts before removing the 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 assem-
blies.
(4) Connect the wires and connectors of the major parts that
have been removed in step (1). (Refer to Fig.2-4-1a.)
(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 as-
sembly.
Notes:
• 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.
• For the disassembly procedure of the major parts and
details of the precautions to be taken, see "2.3 Disas-
sembly/assembly method".
• If there are wire connections from the Main board and
Mechanism assemblies to the other major parts, besure
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-
Digital
board assembly
CN8004
CN8801
CN8003
CN8005
CN402
CN401
CN9301
CN9001
CN8001
CN8002
TP602
A/HS2_FF
TP622
PB_DATA2
VR2251
FMA
REC
LEVEL
CN602
CN901
TO CN8001
TO CN8002
CN3009
Jack board
assembly
CN7191
blies. If they are improperly grounded, there may
benoise 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-
cassette tape, set the Mechanism assembly to the re-
quired 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.
2.4.2 Precautions for cassette loading in the "Service posi-
tion"
The REC safety board assembly detects cassette loading as well
as cassette tabs. Therefore, after the assembly has been re-
moved in the "Service position", it is required to set the switch
manually on the REC safety board assembly when a cassette is
loaded.
2.4.3 Cassette loading and ejection methods in the "Ser-
vice position"
(1) Insert a cassette halfway in the Cassette holder assembly.
(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
nothave 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 detect-
ed and recording becomes possible even with a cassette
with broken tabs such as the alignment tape. Be verycareful
not to erase important tapes.
TP612
REC_LEVEL2
TP611
REC_LEVEL1
TP621
PB_DATA1
Terminal sub board assembly
PRE/REC
board assembly
CN7104
CN7101
CN7102
TP622 TP612
TP621 TP602 T611
CP4001
CN601
CP3002
TP501
Y TO SE
CN3008
REC Safety
board assembly
CN7005
CN7002
Display board assembly
Fig.2-4-1a
Switching regulator
board assembly
TP106
TP4001
PB FM
CTL P
TP111
D.FF
TP2253
A.PB FM
TP2254
A.REC FM
CN5603
Main board assembly
(No.82933)1-9
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