Sony XR-3750 Service Manual
Sony XR-3750 Service Manual

Sony XR-3750 Service Manual

Fm/mw/sw cassette car stereo
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XR-3750
SERVICE MANUAL
Saudi Arabia Model
Model Name Using Similar Mechanism
XR-4800
Tape Transport Mechanism Type
MG-25F-136
SPECIFICATIONS
FM/MW/SW CASSETTE CAR STEREO
MICROFILM

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Summary of Contents for Sony XR-3750

  • Page 1 XR-3750 SERVICE MANUAL Saudi Arabia Model Model Name Using Similar Mechanism XR-4800 Tape Transport Mechanism Type MG-25F-136 SPECIFICATIONS FM/MW/SW CASSETTE CAR STEREO MICROFILM...
  • Page 2: Table Of Contents

    TABLE OF CONTENTS GENERAL Location of Controls ............3 Resetting the Unit ............4 Detaching the Front Panel ..........4 Setting the Clock ............. 4 Dismounting the Unit ............4 Installation ............... 5 Connection ..............6 DISASSEMBLY ............8 ASSEMBLY OF MECHANISM DECK ...
  • Page 3 SECTION 1 This section is extracted from instruction manual. GENERAL – 3 –...
  • Page 5 – 5 –...
  • Page 6 – 6 –...
  • Page 7 – 7 –...
  • Page 8: Disassembly

    SECTION 2 DISASSEMBLY Note: Follow the disassembly procedure in the numerical order given. COVER ASS’Y 3 cover ass’y 5 screw (PTT2.6 × 6) SUB PANEL, MECHANISM DECK (MG-25F-136) 3 connector (CN351) 6 mechanism deck (MG-25F-136) 4 flexible flat cable (CN301) 2 sub panel 1 three screws (PTT2.6 ×...
  • Page 9 MAIN BOARD, HEAT SINK 5 two screws (PTT 2.6 × 8) 5 three screws (PTT 2.6 × 10) 1 screw 3 two ground point (PTT2.6 × 8) screws 5 two screws (PTT 2.6 × 8) 6 heat sink 4 main board 2 rubber cap (25) 1 two screws (PTT2.6 ×...
  • Page 10: Assembly Of Mechanism Deck

    SECTION 3 ASSEMBLY OF MECHANISM DECK Note: Follow the disassembly procedure in the numerical order given. 5 Fit projection on C part. HOUSING 7 Holder the hanger by bending the claw. 2 Install the hanger onto two claws of the housing. 1 Install the catch to the hanger.
  • Page 11 LEVER (LDG-A) / (LDG-B) shaft A shaft B shaft A shaft C shaft B 1 Fit the lever (LDG-A) on shafts A – C and install it. 3 type-E stop ring 2.0 2 Fit the lever (LDG-B) on shafts A and B and install it.
  • Page 12 GUIDE (C) 2 guide (C) 1 three claws MOUNTING POSITION OF CAPSTAN / REEL MOTOR (M901) two precision screws (P2 × 2) capstan / reel motor (M901) 30˚ – 12 –...
  • Page 13: Mechanical Adjustments

    SECTION 4 SECTION 5 ELECTRICAL ADJUSTMENTS MECHANICAL ADJUSTMENTS 1. Clean the following parts with a denatured-alcohol-moistene TEST MODE swab: This set have the test mode function. In the test mode, FM Auto playback head pinch roller Scan/Stop Level and AM (MW) Auto Scan/Stop Level adjustments rubber belt capstan can be performed easier than it in ordinary procedure.
  • Page 14: Tuner Section

    FM Noise Focus Adjustment TUNER SECTION Setting: [SOURCE] button: FM 0 dB=1 µV FM RF signal Cautions during repair level meter antenna jack (J1) generator When the tuner unit is defective, replace it by a new one be- 0.01 µ F 10 k Ω...
  • Page 15 AM (MW) Auto Scan/Stop Level Adjustment Make this adjustment after “FM Auto Scan/Stop Level Adjustment”. Setting: [SOURCE] [MODE] button: MW 30 Ω 15 pF 65 pF AM RF signal generator AM dummy antenna (50 Ω ) antenna jack (J1) Carrier frequency : 999kHz 30% amplitude modulation by 1 kHz signal...
  • Page 16 Adjustment Location: – SET UPPER VIEW – Tape Speed Adjustment TU 1 RV 1 AM (MW) Auto Scan/Stop Level Adjustment RV 2 FM Auto Scan/Stop Level Adjustment RV 3 FM Noise Focus Adjustment RV 4 FM Stereo Separation Adjustment – 16 –...
  • Page 17: Diagrams

    SECTION 6 DIAGRAMS 6-1. IC PIN FUNCTION DESCRIPTION • MAIN BOARD IC501 µPD17708GC-545-3B9 (SYSTEM CONTROLLER) Pin No. Pin Name Function ILLIN Dimmer detection signal input terminal Dimmer is present at input of “L” (fixed at “L”) POS3 POS2 Tape position detect input from tape operation switch on the mechanism block POS0 POS1 TAPEON...
  • Page 18 Pin No. Pin Name Function BU IN Battery detect signal input terminal “H”: battery on METAL control in/out terminal At initial mode: auto/manual mode selection input of METAL function “L”: manual mode At manual mode: METAL on/off control signal output terminal (“H” output: METAL on) MTLSEL At auto mode: input at MTLIN (pin %ª) Not used this function in this set (fixed at “H”)
  • Page 19 Pin No. Pin Name Function BUSON Bus on/off control signal output terminal “L”: bus on Not used (pull up) SYSRST Reset signal output terminal “L”: reset Not used (pull up) VREG CPU regulator output terminal Connected to capacitor — Ground terminal X OUT Main system clock output terminal (4.5 MHz) X IN...
  • Page 20: Note For Printed Wiring Boards And Schematic Diagrams

    6-2. NOTE FOR PRINTED WIRING BOARDS AND SCHEMATIC DIAGRAMS Note on Schematic Diagram: Note on Printed Wiring Board: • X : parts extracted from the component side. • All capacitors are in µF unless otherwise noted. pF: µµF • 50 WV or less are not indicated except for electrolytics : internal component.
  • Page 21: Printed Wiring Board - Main Section

    XR-3750 6-3. PRINTED WIRING BOARD – MAIN Section – • Semiconductor Location Ref. No. Location D301 D351 I-12 D352 G-13 D501 D502 F-10 D551 G-12 D552 G-12 D553 D571 D-11 D572 F-10 D582 F-13 D583 E-13 D601 J-13 D621 D622...
  • Page 22 XR-3750 6-4. SCHEMATIC DIAGRAM – MAIN Section (1/2) – • • See page 32 for Waveforms. See page 31 for IC Block Diagrams. – 23 – – 24 –...
  • Page 23 XR-3750 6-5. SCHEMATIC DIAGRAM – MAIN Section (2/2) – • See page 31 for IC Block Diagrams. (Page 29) – 25 – – 26 –...
  • Page 24: Printed Wiring Board - Panel Section

    XR-3750 6-6. PRINTED WIRING BOARD – PANEL Section – (Page 21) • Semiconductor Location Ref. No. Location D901 D902 F-10 D903 F-10 D904 F-10 D905 F-10 IC901 – 27 – – 28 –...
  • Page 25: Schematic Diagram - Panel Section

    XR-3750 6-7. SCHEMATIC DIAGRAM – PANEL Section – (Page 26) – 29 – – 30 –...
  • Page 26 • IC Block Diagrams IC351 MM1322XFBE • Waveform – MAIN Section – – MAIN Section – IC301 CXA2509AQ-T4 1 IC501 &¶ (X-IN) 8 OUT2 24dB 120µ/70µ 3.2 Vp-p + – MSMODE OUT1 – NR BIAS PBFB2 DRSW MODE PBRIN2 TAPE/AUX TAPESW 222 ns PBREF2...
  • Page 27: Exploded Views

    SECTION 7 EXPLODED VIEWS NOTE: • -XX and -X mean standardized parts, so they • Items marked “*” are not stocked since they may have some difference from the original are seldom required for routine service. Some one. delay should be anticipated when ordering •...
  • Page 28 (2) FRONT PANEL SECTION not supplied (KEY board) LCD901 Ref. No. Part No. Description Remark Ref. No. Part No. Description Remark 3-009-301-01 BUTTON (BASS) 3-016-928-11 BUTTON (4-6) (4. 5. 6) 3-015-036-01 CUSHION (BACK PANEL) 3-016-930-01 BUTTON (R) (3) (BTM. LCL. r) 3-016-924-01 BUTTON (L) (2) (+.
  • Page 29 (3) MECHANISM DECK SECTION (MG-25F-136) HP901 M901 Ref. No. Part No. Description Remark Ref. No. Part No. Description Remark A-3291-667-A CLUTCH (FR) ASSY 3-933-346-01 CATCHER * 152 3-019-130-01 LEVER (LDG-A) 3-933-344-01 GUIDE (C) * 153 3-019-131-01 LEVER (LDG-B) 3-014-798-01 SCREW (HEAD), SPECIAL 3-020-539-01 SPRING (LD-1), TENSION 3-364-151-01 WASHER 3-020-540-01 SPRING (LD-2), TENSION...
  • Page 30: Electrical Parts List

    SECTION 8 ELECTRICAL PARTS LIST NOTE: • Due to standardization, replacements in the • Items marked “*” are not stocked since they When indicating parts by reference are seldom required for routine service. parts list may be different from the parts speci- number, please include the board.
  • Page 31 MAIN Ref. No. Part No. Description Remark Ref. No. Part No. Description Remark R962 1-216-025-00 RES, CHIP 1/10W C151 1-163-037-11 CERAMIC CHIP 0.022uF R963 1-216-033-00 METAL CHIP 1/10W C152 1-124-257-00 ELECT 2.2uF R964 1-216-035-00 METAL CHIP 1/10W C161 1-126-160-11 ELECT R965 1-216-035-00 METAL CHIP 1/10W...
  • Page 32 MAIN Ref. No. Part No. Description Remark Ref. No. Part No. Description Remark C359 1-164-489-11 CERAMIC CHIP 0.22uF < DIODE > C501 1-163-235-11 CERAMIC CHIP 22PF C502 1-163-234-11 CERAMIC CHIP 20PF 8-719-991-65 DIODE SB02W03C C503 1-124-584-00 ELECT 100uF 8-719-423-10 DIODE MA8100-M-TX 8-719-420-90 DIODE MA8051-M C504 1-164-004-11 CERAMIC CHIP...
  • Page 33 MAIN Ref. No. Part No. Description Remark Ref. No. Part No. Description Remark < SHORT > Q602 8-729-900-53 TRANSISTOR DTC114EK Q603 8-729-027-23 TRANSISTOR DTA114EKA-T146 1-216-296-00 SHORT Q621 8-729-027-23 TRANSISTOR DTA114EKA-T146 1-216-295-00 SHORT 1-216-296-00 SHORT Q622 8-729-120-28 TRANSISTOR 2SC1623-L5L6 JC151 1-216-296-00 SHORT JC161 1-216-295-00 SHORT <...
  • Page 34 MAIN Ref. No. Part No. Description Remark Ref. No. Part No. Description Remark R272 1-216-073-00 METAL CHIP 1/10W R545 1-249-429-11 CARBON 1/4W R273 1-216-081-00 METAL CHIP 1/10W R274 1-216-129-00 METAL CHIP 2.2M 1/10W R546 1-249-413-11 CARBON 1/4W R275 1-216-089-00 RES, CHIP 1/10W R551 1-216-097-00 RES, CHIP...
  • Page 35 Ref. No. Part No. Description Remark Ref. No. Part No. Description Remark M901 A-3291-665-A MOTOR ASSY, MAIN (CAPSTAN/REEL) ************************************************************ ************** HARDWARE LIST ************** 7-621-772-10 SCREW +B 2X4 7-685-793-09 SCREW +PTT 2.6X8 (S) 7-685-792-09 SCREW +PTT 2.6X6 (S) 7-685-794-09 SCREW +PTT 2.6X10 (S) 7-685-106-19 SCREW +P 2X10 TYPE2 NON-SLIT 7-624-104-04 STOP RING 2.0, TYPE-E 7-627-553-17 PRECISION SCREW +P 2X2 TYPE 3...
  • Page 36 XR-3750 Sony Corporation 98K05055-1 9-925-546-41 Personal & Mobile Communication Company Printed in Japan © 1998. 11 – 42 – Published by Quality Assurance Dept.

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