Mitsubishi HS-U748 Service Manual
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Mitsubishi HS-U748 Service Manual

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MITSUBISHI
Tape Format
: S-VHS/VHS 1/2" high-density
Power Source
: 120 V AC ; 60 Hz
Power Consumption
: Approx. 21 W (standby 2.9 W)
Video Signal System
: EIA standard ; NTSC color
Video Recording System
: S-VHS standard
Luminance
: Frequency modulation recording
Color Signal
: Low frequency conversion
Hi-Fi Audio
: VHS standard
Recording System
Linear Audio Track
: 1 track
Tape Speed
: 1-5/16 i.p.s (standard play)
Maximum Recording
: 120 min. with T-120 video
Heads: Video
: 4 rotary heads
Hi-Fi Audio
: 2 rotary heads
Audio/Control
: 1 stationary head
Erase
: 1 full track head
MITSUBISHI DIGITAL ELECTRONICS AMERICA, INC.
9351 Jeronimo Ave. Irvine, California 92618 U.S.A.
Copyright C 2002 Mitsubishi Digital Electronics America, Inc. All Rights Reserved.
Only cassettes marked S-VHS or VHS can be used with this video cassette recorder.
SPECIFICATIONS
video cassette tape
sub-carrier phase shift recording
Azimuth helical scanning system
7/16 i.p.s (extended play)
cassette (SP mode)
360 min. with T-120 video
cassette (EP mode)
VIDEO CASSETTE RECORDER
Video Input
Audio Input
Video Output
Audio Output
Tuner
VHF
UHF
CATV
Operating Temperature
Relative Humidity
RF Channel Output
Weight
Dimensions
Timer Program Capacity
Deck
• Weight and dimensions shown are approximate.
• Design and specifications are subject to change without notice.
MODEL
HS-U748
: 0.5 to 2.0 V(p-p), 75 Ω
unbalanced RCA pin Jack
: 346 mV(rms), 47 kΩ
unbalanced RCA pin Jack
: 1.0 V(p-p), 75 Ω unbalanced
RCA pin Jack
: 346 mV(rms), 1 kΩ unbalanced
RCA pin Jack
: 54 to 88 MHz, 174 to 216 MHz
: 470 to 806 MHz
: 54 to 88 MHz, 90 to 804 MHz
: 41 °F to 104 °F
: 30 % to 80 %
: Channel 3 or 4 switchable
: Approx. 8.0 lbs (3.6 kg)
: 16.7"(W) × 3.7"(H) × 11.9"(D)
: 1 month programmable
/ 8 programs
: α Deck
2002

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Summary of Contents for Mitsubishi HS-U748

  • Page 1 • Weight and dimensions shown are approximate. • Design and specifications are subject to change without notice. MITSUBISHI DIGITAL ELECTRONICS AMERICA, INC. 9351 Jeronimo Ave. Irvine, California 92618 U.S.A. Copyright C 2002 Mitsubishi Digital Electronics America, Inc. All Rights Reserved.

  • Page 2: Table Of Contents

    CONTENTS – FILE “COVERPGE” – IDLER2 UNIT ..........9 SPECIFICATIONS ............1 2-15 CAPSTAN BRAKE SPRING, CONTENTS..............2 CAPSTAN BRAKE ASSY ......11 GLOSSARY OF ABBREVIATIONS ........4 2-16 FC HOLDER, MOTOR HOLDER, LOADING WORM, – FILE “DISASSY” – LOADING MOTOR ASSY, SAFETY PRECAUTIONS ..........1 WORM WHEEL..........12 CONNECTION ..............3 2-17 PINCH ARM CAP, PINCH ASSY....13...

  • Page 3: Contents

    CONTENTS 3-2-1 GUIDE ROLLER Adjustment Check ....31 3-2-2 Height Adjustment of GUIDE ROLLER (SP) ........31 3-2-3 Height Adjustment of GUIDE ROLLER (TU) ........31 3-2-4 Coarse Adjustment of Phase .......32 3-2-5 Flatness Check of FM Waveform....32 3-2-6 Tape Running Condition at the GUIDE ROLLERs (Check1) ....33 3-2-7 Tape Running Condition at the GUIDE ROLLERs (Check 2) ....33 A/C HEAD Adjustment .........34...

  • Page 4: Glossary Of Abbreviations

    GLOSSARY OF ABBREVIATIONS : Audio/Control JSTCLK : Just Clock A-PB : Audio Play Back A-REC : Audio Recording LIN-IN : Linear Audio In : Audio Erase LIN-OUT : Linear Audio Out AENV : Audio Envelope LMUTE : Linear Mute : Automatic Frequency Control : Long Play : Audio Flip Flop AFTV...

  • Page 5: Safety Precautions

    SAFETY PRECAUTIONS INTRODUCTION SAFETY NOTICE This manual provides service information for the adjustments Before returning VCR to the customer a safety check of the of mechanical and electrical operations. entire VCR should be made. The service technician must be Due to design modifications, the servicing procedures and sure that no protective device built into the instrument by the data given in this manual are subject to possible change manufacturer has become defective or inadvertently...
  • Page 6 2. Hot Check The test sequence, with reference to the measuring (2) Close switch S1, energizing the VCR, and immediately circuit in the figure is as follows: after closing the switch, measure leakage current using (1) With switch S1 open, connect the VCR to the measuring both positions of switch S2, and with the switching circuit.

  • Page 7: Connection

    CONNECTION Connecting separate antennas (UHF/VHF) Now that you’ve completed the antenna connections to your Connecting the Television VCR, you’re ready to connect the VCR to the TV. To connect separate UHF/VHF antennas to the VCR: Because every television is different (especially older model 1.

  • Page 8: Disassembly

    DISASSEMBLY 1. Removal of Top Cover Top Cover 1. Remove the two Top Cover fastening screws (a) shown in Fig. 1 and remove the Top Cover in the direction shown by arrow. 2. Removal of Front Panel 1. Remove the Top Cover. (Refer to Para.
  • Page 9 3. Removal of Bottom Panel 1. Remove the two fastening screws (a) shown in Fig. 2. 2. Turn the set upside down as shown in Fig. 3. 3. Slide the Bottom Panel backward to remove it, taking care of the five catches (b). Fig.
  • Page 10 4. Removal of DECK ASSY 1. Remove the Top Cover. (Refer to Para. 1 of the DISASSEMBLY.) 2. Remove the Front Panel. (Refer to Para. 2 of the DISASSEMBLY.) Shield Cover 3. Short-circuit the cathode side of D927 and the GND of the DECK ASSY using the jig shown below.

  • Page 11: How To Execute Circuit Board Service

    HOW TO EXECUTE CIRCUIT BOARD SERVICE CAUTION: BEFORE ATTEMPTING TO REMOVE OR REPAIR ANY PCB, UNPLUG THE POWER PCB-MAIN CORD FROM THE A.C. SOURCE. LOCATION OF PRINTED CIRCUIT BOARDS Note : • Take caution when removing flat cables to prevent any contact problem.
  • Page 12 2. PCB-MAIN 1. Remove the Bottom Panel. (Refer to Para. 3 of the DISASSEMBLY.) 2. Remove the DECK ASSY. (Refer to Para. 4 of the DISASSEMBLY.) 3. Remove the two screws (a) shown in Fig. 8. 4. Remove the Holder for the AC Power Cord from the Base Chassis shown in Fig.

  • Page 13: Chip Parts Replacement

    CHIP PARTS REPLACEMENT CHIP PARTS REPLACEMENT 2. Removal of Chip Parts (Transistors) Some resistors, shorting jumpers (0Ω resistor), ceramic A. Melt the solder of one lead. Lift the side of that lead capacitors, transistors and diodes are chip parts. upward. When replacing these parts, note the following cautions.

  • Page 14: File "Coverpge" - Specifications

    MECHANICAL ADJUSTMENT AND REPLACEMENT 1. DECK Cleaning 1-2. Tape Running System Clean the following Parts of the Tape Running System. The following Parts require cleaning whenever serviced in 1. TENSION PIN order to maintain satisfactory performance. 2. F/E HEAD 1-1. VIDEO HEAD 3.

  • Page 15: Servo Circuit Adjustment

    2. Replacement of Major Parts 2-1. CLEANING ARM, FELT RING FELT RING SET POSITION : Normal (Removal) CLEANING 1. Release the two catches (a) of the CLEANING ARM shown in the Fig. 2-1 to remove the CLEANING ARM. 2. Release the two catches (b) of the CLEANING ARM shown in the Fig.

  • Page 16: Bottom Assy

    2-3. BOTTOM ASSY Hole in MAIN PLATE ASSY SET POSITION : Normal Remove the following part before replacing the BOTTOM ASSY. Refer to the corresponding item to install it. • STAY PLATE (Item 2-2) (Removal) 1. Move the WORM WHEEL in the Fig. 2-3-1 in the direction shown by the arrow A.

  • Page 17: Insert Guide (Tu)

    2-4. INSERT GUIDE (TU) SET POSITION : Normal Remove the following parts before replacing the INSERT INSERT GUIDE (TU) GUIDE (TU). Refer to the corresponding items to install them. • STAY PLATE (Item 2-2) • BOTTOM ASSY (Item 2-3) (Removal) 1.

  • Page 18: Rec Holder, Rec Lever, Rec Spring

    2-6. REC HOLDER, REC LEVER, REC SPRING SPRING REC LEVER SET POSITION : Upside down (Removal) 1. Remove the screw (a) fastening the REC HOLDER shown in the Fig. 2-6 to remove the REC HOLDER. 2. Release the REC SPRING shown in the Fig. 2-6 from REC HOLDER the catch (b) of the REC HOLDER to remove the REC LEVER.

  • Page 19: A/C Head Unit

    2-8. A/C HEAD UNIT LEAD CONNECTOR SET POSITION : Normal (Removal) 1. Remove the LEAD CONNECTOR of the A/C HEAD UNIT shown in the Fig. 2-8. A/C HEAD UNIT 2. Remove the two screws (a) fastening the A/C HEAD UNIT shown in the Fig. 2-8 to remove the A/C HEAD Head UNIT.

  • Page 20: Sensor Cover (Tu)

    2-10.SENSOR COVER (TU) SET POSITION : Normal (Removal) 1. Release the catch (a) of the SENSOR COVER (TU) shown in the Fig. 2-10 to remove the SENSOR COVER (TU). (Installation) 1. Install the SENSOR COVER (TU) shown in the Fig. 2- SENSOR COVER (TU) Fig.

  • Page 21: Rev Unit (Tu),Rev Unit (Sp)

    2-12.REV UNIT (TU), REV UNIT (TU) REV UNIT (SP) SET POSITION : Upside down (Removal) REV UNIT (SP) 1. Release the two catches (a) of the REV UNIT (TU) shown in the Fig. 2-12 to remove the REV UNIT (TU). 2.

  • Page 22: Thrust Washer

    2-14.REEL BELT, PULLEY BUSH, THRUST REEL BELT WASHER, BELT PULLEY, SHIFT SLIDER, PULLEY GEAR ASSY, SLIP PULLEY BUSH GEAR, SLIP SPRING, SLIP 2 WASHER, THRUST WASHER, SLIP THRUST WASHER ADJUSTER, IDLER 2 UNIT BELT PULLEY SET POSITION : Upside down Pull in the direction (Removal) of the Arrow (A) to...
  • Page 23 9. Install the units from the SLIP 2 WASHER to REEL BELT shown in the Fig. 2-14-1. SLIP ADJUSTER Note1 : Be sure to replace the removed PULLEY BUSH Center of the with a new one. BELT PULLEY Note2 : Attach the SLIP SPRING with its straight end facing the SLIP GEAR side.

  • Page 24: Capstan Brake Spring

    2-15.CAPSTAN BRAKE SPRING, CAPSTAN BRAKE ASSY CAPSTAN BRAKE ASSY SET POSITION : Upside down (Removal) 1. Remove the CAPSTAN BRAKE SPRING shown in the CAPSTAN MOTOR Fig. 2-15. 2. Remove the catch (a) of the CAPSTAN BRAKE CAPSTAN BRAKE SPRING ASSY shown in the Fig.

  • Page 25: Fc Holder, Motor Holder

    2-16.FC HOLDER, MOTOR HOLDER, LOADING MOTOR ASSY LOADING WORM, LOADING MOTOR ASSY, WORM WHEEL SET POSITION : Normal (Removal) 1. Release the two catches (a) of the FC HOLDER LOADING FC HOLDER WORM shown in the Fig. 2-16-1 to remove the FC HOLDER. 2.

  • Page 26: Pinch Arm Cap, Pinch Assy

    2-17.PINCH ARM CAP, PINCH ASSY SET POSITION : Normal PINCH ARM (Removal) 1. Release the two catches (a) of the PINCH ARM CAP Part shown in the Fig. 2-17 to remove the PINCH ARM CAP. 2. Remove the PINCH ASSY shown in the Fig. 2-17. Part PINCH ASSY (Installation)

  • Page 27: Brake Cam Plate

    3. Apply GREASE (MULTEMP AC-DM)[859D055O90] to the points on the MAIN PLATE ASSY specified in the Hole Fig. 2-18-1. 4. Apply GREASE (MULTEMP AC-DM)[859D055O90] to the points on the DOOR ARM specified in the Fig. 2- MAIN CAM 18-1. 5. Install the DOOR ARM. F/L PLATE 6.

  • Page 28: Guide Lamp

    BRAKE SPRING Insert the BRAKE SPRING under the Catch. Catch BRAKE (TU) Fig. 2-19-3 2-20.GUIDE LAMP SET POSITION : Normal Remove the following parts before replacing the GUIDE LAMP. Refer to the corresponding items to install them. • STAY PLATE (Item 2-2) •...

  • Page 29: Main Cam, Guide Arm (Tu)

    2-21.MAIN CAM, GUIDE ARM (TU), MAIN CAM BRAKE LEVER, LB PIN SET POSITION : Normal Remove the following parts before replacing the MAIN CAM, GUIDE ARM (TU), BRAKE LEVER. Refer to the corresponding items to install them. BRAKE LEVER GREASE •...

  • Page 30: L/D Lock Lever

    2-22.L/D LOCK LEVER L/D LOCK LEVER SET POSITION : Normal Remove the following parts before replacing the L/D LOCK LEVER. Refer to the corresponding items to install them. • STAY PLATE (Item 2-2) • BOTTOM ASSY (Item 2-3) • MOTOR HOLDER (Item 2-16) •...

  • Page 31: Belt Lever, Belt Adjuster

    2-24. BELT LEVER, BELT ADJUSTER SET POSITION : Normal Remove the following parts before replacing the BELT BELT LEVER LEVER, BELT ADJUSTER. Refer to the corresponding items to install them. BELT ADJUSTER • STAY PLATE (Item 2-2) • BOTTOM ASSY (Item 2-3) •...

  • Page 32: Brake Belt (Tu)

    (Installation) 1. Apply OIL (FLOIL 948P) [859D154O20] to the parts on the MAIN PLATE ASSY specified in the Fig. 2-25. 2. Install the REEL DISK (SP side). 3. Install the TENS AXIS HOLDER. Note : Install the TENS AXIS HOLDER so that the catch (a) for the TENSION ARM will be positioned on the front (F/L ARM ASSY side).

  • Page 33: Shift Lever

    (Installation) Note : Install the BRAKE BELT (TU) so that its Felt Side touches the REEL DISK (TU side). The GREASE applied to the BRAKE CAM PLATE and the MAIN PLATE ASSY should not adhere on the Felt Side of the BRAKE BELT (SP). 1.

  • Page 34: Charge Spring, Swing Lever

    2-29.CHARGE SPRING, SWING LEVER, CHARGE ASSY CHARGE SPRING SET POSITION : Normal Remove the following parts before replacing the CHARGE CHARGE ASSY SPRING, SWING LEVER, CHARGE ASSY. Refer to the corresponding items to install them. • STAY PLATE (Item 2-2) •...

  • Page 35: A/L Lever

    (Installation) 1. Apply GREASE (MULTEMP AC-DM)[859D055O90] to LOADING ARM ASSY (TU) the parts on the MAIN PLATE ASSY specified in the Fig. 2-30-1. 2. Apply GREASE (MULTEMP AC-DM)[859D055O90] to the parts on the LOADING ARM ASSY (TU) specified in the Fig. 2-30-2. 3.
  • Page 36 (Installation) A/L LEVER Note : Install the LOADING ARM ASSY (TU) and LOADING ARM ASSY (SP), according to the following procedure, after installing the A/L Back LEVER. 1. Apply GREASE (MOLYKOTE G PASTE) [859D055O50] to the parts on the MAIN PLATE ASSY specified in the Fig.

  • Page 37: Tape Guide Assy (Sp)

    2-32.TAPE GUIDE ASSY (SP), TAPE GUIDE ASSY (TU) TAPE GUIDE ASSY (TU) TAPE GUIDE ASSY (SP) SET POSITION : Normal Remove the following parts before replacing the TAPE GUIDE ASSY (SP), (TU). Refer to the corresponding items to install them. •...

  • Page 38: Drum Clamper, Drum Assy

    2-33.DRUM CLAMPER, DRUM ASSY LEAD CONNECTOR SET POSITION : Normal (Removal) 1. Disconnect the LEAD CONNECTOR of the DRUM ASSY shown in the Fig. 2-33-1. DRUM ASSY with 2. Remove the two screws (a, b) fastening the DRUM DRUM CLAMPER CLAMPER shown in the Fig.

  • Page 39: Spacer, Rotor Case, End Ring, Brush, Upper Drum Assy

    Part A Reference Reference Pin and Catch have to Catch touch each other. Fig. 2-33-3 2-34.DRUM MOTOR STATOR, BRUSH Side View of END RING SPRING, SPACER, ROTOR CASE, END RING, BRUSH, UPPER DRUM ASSY DRUM MOTOR This side down. STATOR SET POSITION : Normal (Removal) LEAD...

  • Page 40: Capstan Motor

    (Installation) 1. Install the SPACER shown in the Fig. 2-34-1. Note : Be sure to use the new SPACER packed with the new UPPER DRUM ASSY. 2. Install the UPPER DRUM ASSY shown in the Fig. 2- 34-1. 3. Install the END RING so that the reference hole (A) of the END RING shown in the Fig.
  • Page 41 (Installation) 1. Apply SILICON COMPOUND (SC102) [859D164O10] to the parts on the MAIN PLATE ASSY specified in the Fig. 2-35-3. WORM WHEEL 2. Install the CAPSTAN MOTOR. GUIDE ARM (TU) Arrow CAPSTAN MOTOR Fig. 2-35-2 SILICON COMPOUND (SC102) MAIN PLATE ASSY Fig.

  • Page 42: Impedance Unit (Sp)

    2-36.IMPEDANCE UNIT (SP), FLYWHEEL (SP) SET POSITION : Normal FLYWHEEL (SP) (Removal) 1. Unfasten the two catches (a) on the IMPEDANCE UNIT (SP) shown in Fig. 2-36, and remove the IMPEDANCE UNIT FLYWHEEL (SP). (SP) 2. Remove the screw (b) on the IMPEDANCE UNIT (SP) shown in Fig.

  • Page 43: Interchangeability Adjustment Of The Mechanism

    3. Interchangeability Adjustment of the Mechanism Note 1 : Tracking may need to be preset during TENSION ARM interchangeability adjustment of the mechanism. Digital tracking is preset by short circuiting TP5A and TP5B on the PCB-MAIN. Note 2 : The adjustments are performed in the TENSION POLE PLAYBACK mode, using the staircase signal of an alignment tape,unless otherwise...

  • Page 44: Check And Adjustment Of Fm Envelope

    3-2. Check and Adjustment of the FM Envelope 3-2-1. GUIDE ROLLER Adjustment check 1. Play back an alignment tape (NM6KE2 : 859C339O90). 2. Preset the tracking. 3. Confirm that the FM Waveform is flat such as in (A). 4. Perform the Item 3-2-2. "Height Adjustment of GUIDE ROLLER (SP) "...

  • Page 45: Coarse Adjustment Of Phase

    3-2-4. Coarse Adjustment of Phase 1. Play back an alignment tape (NM6KE2 : 859C339O90). 2. Preset the tracking. 3. Observe the FM Waveform after performing Item 3-2- 1. "GUIDE ROLLER Check". Screw D 4. If the amplitude level of the FM Waveform is low as in (F) in Fig.

  • Page 46: Tape Running Condition At The Guide Rollers (Check1)

    3-2-6. Tape Running Condition at the GUIDE ROLLERs (Check 1) GUIDE ROLLER 1. Play back an Alignment Tape. Tape [NM6KE2: 859C339O90] 2. Confirm visually that there is a space between the Tape and the Lower FLANGE of the GUIDE ROLLER (SP) and the GUIDE ROLLER (TU).

  • Page 47: A/C Head Adjustment

    3-3. A/C HEAD Adjustment 3-3-1. Slant Adjustment of A/C HEAD 1. Play back a blank tape. Screw C 2. Slowly turn the slant adjustment Screw C shown in the Fig. 3-3-1 counter-clockwise to slightly crease the bottom of the tape at the Lower FLANGE of the GUIDE POLE (TU).

  • Page 48: Phase Adjustment

    3-4. Phase Adjustment 1. Play back an alignment tape (NM3KE6 : 859C339O50). 2. Preset the tracking. Screw D 3. Loosen the Screws D and E shown in the Fig. 3-4-1. Insert a screw driver (+) into the Hole in the MAIN PLATE ASSY (Part A) and move the A/C PLATE to the right and left to set the amplitude level of the FM Tape...

  • Page 49: Servicing For Tape Jam During The Loading Process

    4. Servicing for Tape Jam WORM WHEEL during the Loading Process 1. Remove the tape if the mechanism part is locked due tangled tape. 2. Rotate the WORM WHEEL of the LOADING MOTOR ASSY shown in the Fig. 4 in the direction of the arrow A to eject the cassette tape.

  • Page 50: Service Can Be Executed With The Ee Picture Displayed

    SERVICE CAN BE EXECUTED WITH THE EE PICTURE DISPLAYED 1. Short-circuit the cathode side of D927 and the GND of the DECK ASSY using the jig shown in Fig. 2. 2. Remove the DECK ASSY. 3. Connect TP5X and TP5Y with a jumper Note1: Short-circuit the test points before turning on the power.
  • Page 51 HOW TO INITIALIZE THE E PROM A replacement E PROM is not initialized before shipping, so the E PROM must be initialized when replaced. Initialize the E PROM by following the steps below. 1. Press and hold the POWER button on the set for 8 seconds. 2.
  • Page 52 [ Servo circuit ] Adjustment purpose Video switch over timing during playback. 1. Playback Switching Point Symptom when Switching noise or jitter in the playback picture. incorrectly adjusted 1. Play back an Alignment Tape. (NS1, stair step) Measuring instrument and condition VCR set up condition 2.

  • Page 53: Parts List

    PARTS LIST 1. CABINET ASSEMBLY - 1 -...
  • Page 54 : Critical Component ITEM PARTS NO. PARTS NAME DESCRIPTION CABINET ASSEMBLY 968C049O03 TOP COVER ASSY × 10 669D501O30 SCREW 4 × 12 46LA005 669D221O40 SCREW 572D385O10 F/L SPRING 752C668O40 CASSETTE DOOR ASSY 573D078O10 FRONT EARTH SPRING 701B440O30 FRONT UNIT 752C670O70 TIMER PANEL 3 ×...

  • Page 55: Packing Parts

    2. PACKING PARTS ACCESSORY - 3 -...
  • Page 56 ITEM PARTS NO. PARTS NAME DESCRIPTION PACKING PARTS 831D190O30 PACKING SHEET 800X800 803A585O10 CUSHION 802B827O20 PACKING CASE – – – – – – – ACCESSORY ACCESSORY 939P755O20 REMOTE HAND UNIT 243C273O10 CABLE 243C274O10 Y/C CABLE S-S1.5M 242C938O10 PHONO CABLE 2P R&W L=1.5M –...
  • Page 57 DECK ASSEMBLY...

  • Page 58: Deck Assembly-1

    DECK ASSEMBLY G-022 N-012 DECK ASSEMBLY-1 N-011 A-022 B-025 N-013 B-010 G-072 G-201 G-075 G-201 G-067 B-015 A-025 G-201 G-072 M-037 G-074 C-011 G-091 G-201 C-010 A-026 H-051 G-012 A-023 A-027 H-011 A-021 H-012 G-079 H-031 H-021 M-033 A-019 M-012 M-025 G-071 M-033...
  • Page 59 DECK ASSEMBLY-1 DECK ASSEMBLY-1 ∗ ∗ Settled Service Parts Settled Service Parts ∗ ∗ ITEM PARTS NO. ADDRESS PARTS NAME DESCRIPTION Qt. ITEM PARTS NO. ADDRESS PARTS NAME DESCRIPTION Qt. 2.6 × 5 669D224O90 K G-3 669D173O80 K H-2 A-019 SCREW H-051 SCREW...

  • Page 60: Deck Assembly-2 P/L

    DECK ASSEMBLY DECK ASSEMBLY-2 G-101 M-031 G-093 M-014 G-201 G-088 G-060 G-031 G-212 G-214 G-018 G-056 G-043 G-215 G-057 G-025 G-061 G-017 G-096 G-035 G-081 A-029 G-211 A-028 G-216 G-066 G-019 G-044 G-034 G-094 G-201 G-042 M-034...
  • Page 61 DECK ASSEMBLY-2 ∗ Settled Service Parts ∗ ITEM PARTS NO. ADDRESS PARTS NAME DESCRIPTION Qt. A-028 621C810O10 SSW HOLDER A-029 622D837O10 SSW SLIDER G-017 948D089O01 K H-4 LOADING ARM ASSY (SP) SUPPLY G-018 948D090O01 K G-3 LOADING ARM ASSY (TU) TAKE UP G-019 622D916O10 K B-5 IDLER 2 UNIT G-025 948D098O03 K B-4...
  • Page 62 3. ELECTRICAL PARTS SYMBOL PARTS SYMBOL PARTS PARTS NAME DESCRIPTION PARTS NAME DESCRIPTION Q3A0 261P065O30 CHIP TRANSISTOR DTA124EKA INTEGRATED CIRCUITS Q3A2 260P818O30 CHIP TRANSISTOR 2SC2412K-S Q3L0 261P067O30 CHIP TRANSISTOR DTC124EKA IC2A0 270P881O10 IC HA118421BSNF Q5A3 260P802O20 CHIP TRANSISTOR 2SA1235-F IC2A1 270P882O10 IC MM1501XNRE IC2A3 270P882O10 IC MM1501XNRE...
  • Page 63 : Critical Components SYMBOL PARTS SYMBOL PARTS PARTS NAME DESCRIPTION PARTS NAME DESCRIPTION D8A6 264P568O30 DIODE 1SS254 D8B0 264P568O30 DIODE 1SS254 L3A1 325C471O30 PEAKING COIL 10µH-J D8B1 264P568O30 DIODE 1SS254 L3A2 325C472O50 PEAKING COIL 100µH-J D901 264P508O70 DIODE S1WB(A)60F4072 L5A0 325C472O50 PEAKING COIL 100µH-J L5A1...
  • Page 64 SYMBOL PARTS SYMBOL PARTS PARTS NAME DESCRIPTION PARTS NAME DESCRIPTION R357 103P503O30 CHIP RESISTOR 1/16W 4.7kΩ-J R2C5 103P503O10 CHIP RESISTOR 1/16W 3.3kΩ-J R358 103P503O30 CHIP RESISTOR 1/16W 4.7kΩ-J R2C8 103P491O50 CHIP METAL RESISTOR 1/16W 390Ω-F R365 103P500O90 CHIP RESISTOR 1/20W 47Ω-J R2C9 103P491O90 CHIP METAL RESISTOR 1/16W 560Ω-F...
  • Page 65 SYMBOL PARTS SYMBOL PARTS PARTS NAME DESCRIPTION PARTS NAME DESCRIPTION R5L4 103P504O90 CHIP RESISTOR 1/16W 100kΩ-J R5P0 103P502O70 CHIP RESISTOR 1/16W 1.5kΩ-J R6E6 103P502O30 CHIP RESISTOR 1/16W 680Ω-J R6E7 103P504O30 CHIP RESISTOR 1/16W 33kΩ-J R5P1 103P502O10 CHIP RESISTOR 1/16W 470Ω-J R6E8 103P492O60 CHIP METAL RESISTOR 1/16W1.1kΩ-F...
  • Page 66 SYMBOL PARTS SYMBOL PARTS PARTS NAME DESCRIPTION PARTS NAME DESCRIPTION R8E9 103P401O00 CHIP RESISTOR 1/10W 56Ω-J C2F3 141P144O20 CHIP CAPACITOR F16V 0.1µF-Z R910 103P503O70 CHIP RESISTOR 1/16W 10kΩ-J C2F7 141P144O20 CHIP CAPACITOR F16V 0.1µF-Z R911 103P492O70 CHIP METAL RESISTOR 1/16W 1.2kΩ-F R916 103P491O90 CHIP METAL RESISTOR 1/16W 560Ω-F...
  • Page 67 : Critical Components SYMBOL PARTS SYMBOL PARTS PARTS NAME DESCRIPTION PARTS NAME DESCRIPTION C6A7 154P344O50 CHIP CAPACITOR CH25V 270pF-J C3B8 141P143O30 CHIP CAPACITOR B16V 0.1µF-K C6A8 154P343O90 CHIP CAPACITOR CH50V 150pF-J C3B9 141P143O30 CHIP CAPACITOR B16V 0.1µF-K C6A9 154P343O30 CHIP CAPACITOR CH50V 82pF-J C3C0 141P143O30 CHIP CAPACITOR...
  • Page 68 : Critical Components SYMBOL PARTS SYMBOL PARTS PARTS NAME DESCRIPTION PARTS NAME DESCRIPTION S8A4 432P203O30 KEY BOARD SWITCH STOP S8A5 432P203O30 KEY BOARD SWITCH S8A6 432P203O30 KEY BOARD SWITCH CH-UP S8A7 432P203O30 KEY BOARD SWITCH CH-DN MISCELLANEOUS 243C156O20 CARD LEAD WIRE (MS OS) 11P L=100 243C193O30 CARD LEAD WIRE (MD DD) 7PIN L=120...
  • Page 69 Luminance Record, Chroma Record HS-U748 IC6A0 IC2000 Sub Emphasis YCS/DNR NL PROCESS 1H DLY CLIP DYNAMIC COMB FILTER Q6A0 C-N.C IC2A3 INTER POLATIPN DELAY ADJ Luminance Select IC6A4 Q2B0 Input Select Q2A9 PCB-OPE OS MS J801 F-V-IN M.E FBC MAIN CLAMP M.E ALC...
  • Page 70 Luminance Playback, Chroma Playback HS-U748 IC6A0 IC2000 Sub Emphasis YCS/DNR NL PROCESS 1H DLY CLIP DYNAMIC COMB FILTER Q6A0 IC2A3 DELAY ADJ INTER POLATIPN Luminance Select +ATT IC6A3 Input Select CLAMP Q6C7~Q6C9 J6004 V-OUT DECK CLAMP Q6B1 Q2A6 Q6B0 Video...
  • Page 71 Hi-Fi and Linear Sound HS-U748 IC3A0 Hi-Fi Sound and Linear Selector CONV-AUDIO (TU01 J6004 I2C-DATA (From IC5A0) R-ch A-OUT-R I2C-CLK R-OUT R-CHANNEL OUTPUT A-L 5 (REAR) SELECT L-CHANNEL L-OUT L-ch PB LPF FM LIM L-ch A-OUT-L NOISE PCB-OPE HOLD R-IN L-IN...
  • Page 72 Power, Timer, Mechanical Control T901 HS-U748 +30V To TUNER TU01 15 D927 D910 PCB-MAIN D901 – CP-MOTOR-V D908 AC 120V MOTOR-V D913 STBY5 Q906 Q5A3 Q910 Q901 D5D0 Q5A5 Q905 Q903 D918 Q907 DECK D907 From C5A0 IC2A0 BACKUP D917...
  • Page 73 C O M P O N E N T S R E A D C A R E F U L LY T H E (CONTROL) PRODUCT SAFETY NOTICE IN THE SERVICE MANUAL. PRINTED CIRCUIT BOARD DON'T DEGRADE THE SAFETY OF THE PARTS LAYOUT RECEIVERS THROUGH IMPROPER SERVICING. HS-U748...
  • Page 74 JP910 D918 R914 MOTORV D935 D917 C915 Q907 R916 D920 CPMOTORV L902 Q904 Q919 D907 R909 R926 R927 D933 R910 C914 D921 R925 R912 C927 R943 PC901 L904 C912 Q920 C921 C936 Q909 R911 IC901 R915 R944 IC901 HA17431PA HS-U748...
  • Page 75 R3B4 C3C8 Q3L0 R3B3 C3L0 C3F2 C3A5 R106 C3F3 C3A4 Q102 R105 C102 R108 R107 IC3A0 R3B0 C3A3 R3A9 C3A2 C3F8 C103 C3A7 C3A0 C3A1 C3F6 R3C5 L100 R3C6 R3B2 R3B1 A-OUT-R R3C3 A-OUT-L R3C4 A-IN-R A-IN-L TU-V VIDEO-OUT HS-U748...
  • Page 76 CONTROL SG3 / KS3 DOUT SERIAL SG4 / KS4 DATA SEGMENT SG5 / KS5 INTERFACE DRIVER DISPLAY SG6 / KS6 MEMORY KEY SCAN OUTPUT TIMING SG10 GENERATOR KEY MATRIX MEMORY DRIVER DIMMING CIRCUIT 10,21 22,28 K1 K2 K3 K4 HS-U748...
  • Page 77 IC6J0 R6K4 R6K5 Q6J1 R6H2 R6J1 R6J8 R6K9 C6D6 C6D4 R6G6 Q6J0 IC6A4 Q6J2 C6D3 R6J6 R6J0 R6G5 R6J9 IC6A3 R6J3 R6J7 R6J2 R6J4 C6J2 C6J3 C6J1 Q6J3 R6J5 L6D1 R6G1 R6G0 C6G0 R6G4 C6G3 YCS-Y Y-OUT YCS-IN C-OUT HS-U748...
  • Page 78 ( ± 210@70ns ) [ B ] [ A ] KILLER SKEW DYNAMIC COMB CORRECT C-N.C FILTER SKEW CORRECT MEMORY Bias [ B ] Sync Clamp SKEW DET BIAS VDD1 VSS1 Y-IN Y/C-IN KILLER VDD4 C-IN TEST VSS3 /PV IN VDD3 C.SYNC HS-U748...
  • Page 79 Q2B2 L2A0 Q2B7 R2J2 R357 C2A2 L2A5 C359 Q2B1 C2C1 R2B4 R358 Q353 Q354 IC2A3 IC2A0 q PLAY IC2A0 r REC IC2A0 !4 PLAY IC2A0 !4 REC IC2A0 @0 REC IC2A0 @2 REC 0.5V(p-p)(H) 1.3V(p-p)(H) 0.5V(p-p)(H) 0.54V(p-p)(H) 0.64V(p-p)(H) 1V(p-p)(H) HS-U748...
  • Page 80 0.1µ 14 W N.C. 23 LOGIC 15 N.C. Vcod 22 D OUT CORE 16 N.C. VLIM 21 V LIMIT MOTOR GND 17 N.C. Vco 20 Vco (12V) 1000p 1/16W 1/16W 1/16W 18 RS RSm 19 12k 0.063W 0.47 0.5W HS-U748...
  • Page 81 D – 6 Q355 B – 4 R105 A – 6 R2B6 C – 5 R3A3 B – 3 R5G5 E – 3 R6C3 A – 7 R6K5 C – 7 RJ09 C – 6 TP5TU E – 3 HS-U748...

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