Sony XR-4790 User manual

MICROFILM
SERVICE MANUAL
FM/MW/LW CASSETTE CAR STEREO
AEP Model
UK Model
Model Name Using Similar Mechanism NEW
Tape Transport Mechanism Type MG-25G-136
SPECIFICATIONS
XR-4790/4800
Photo: XR-4800

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TABLE OF CONTENTS
1. GENERAL
Location of Controls (XR-4790) .................................... 3
Location of Controls (XR-4800) .................................... 4
Installation....................................................................... 5
Connections ..................................................................... 6
2. DISASSEMBLY ......................................................... 8
3. ASSEMBLY OF MECHANISM DECK........... 10
4. MECHANICAL ADJUSTMENTS....................... 13
5. ELECTRICAL ADJUSTMENTS
Test Mode ........................................................................ 13
Tape Deck Section .......................................................... 13
Tuner Section .................................................................. 14
6. DIAGRAMS
6-1. Printed Wiring Boards –Main Section–.......................... 20
6-2. Schematic Diagram –Main Section– ............................. 23
6-3. Printed Wiring Board –Panel Section– (XR-4790)....... 28
6-4. Schematic Diagram –Panel Section– (XR-4790)......... 31
6-5. Printed Wiring Board –Panel Section– (XR-4800)....... 33
6-6. Schematic Diagram –Panel Section– (XR-4800)......... 35
6-7. IC Pin Function Description ........................................... 37
7. EXPLODED VIEWS................................................ 40
8. ELECTRICAL PARTS LIST ............................... 44
Flexible Circuit Board Repairing
•Keep the temperature of the soldering iron around 270 ˚C dur-
ing repairing.
•Do not touch the soldering iron on the same conductor of the
circuit board (within 3 times).
•Be careful not to apply force on the conductor when soldering
or unsoldering
Notes on chip component replacement
•Never reuse a disconnected chip component.
•Notice that the minus side of a tantalum capacitor may be dam-
aged by heat.

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SECTION 1
GENERAL This section is extracted from
instruction manual.
(XR-4790)

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(XR-4800)

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Note: Follow the disassembly procedure in the numerical order given.
SECTION 2
DISASSEMBLY
FRONT PANEL ASS’Y
COVER ASS’Y
1 Push the button
(release).
2 Remove the front panel ass'y
to the direction of the arrow A .
A
2
1
2
1
3
cover ass'y

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SUB PANEL, MECHANISM DECK (MG-25G-136)
MAIN BOARD, HEAT SINK
5 screw
(PTT2.6
× 6)
3 connector
(CN351)
2 sub panel
4 flexible flat cable
(CN301)
6 mechanism deck
(MG-25G-136)
1 three screws
(PTT2.6
× 8)
1 three screws
(PTT2.6
× 8)
1 screw (PTT2.6 × 8)
6 heat sink
4 main board
3 two ground point
screws
5 six screws (PTT2.6 × 8)
2 rubber cap (25)
1 two screws
(PTT2.6
× 8)

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SECTION 3
ASSEMBLY OF MECHANISM DECK
Note: Follow the assembly procedure in the numerical order given.
HOUSING
ARM (SUCTION)
A part
C part
B part
D part
8 Hold the hanger by
bending the claw.
6 Fit projection on D part.
4 Fit claw on B part.
3 Put the housing
under A part.
5 Fit projection on C part.
1 Install the catch to the hanger.
2 Install the hanger onto
two claws of the housing.
7 Holder the hanger by bending the claw.
hanger
housing
2 Move the arm (suction) in the arrow
direction and fit on profection.
1 Fit the arm (suction) on the shaft.
projection