SONY TCM-20DV Cassette Recorder User Manual

SONY TCM-20DV Cassette Recorder

• Model Name Using Similar Mechanism NEW
• Tape Transport Mechanism Type MT-20DV-118

Recording system
2-track 1 channel monaural

Tape speed
4.8 cm/s or 2.4 cm/s

Frequency range
250 – 6,300 Hz using nomal (TYPE I) cassette (with REC TIME switch at “NORMAL”)

Speaker
Approx. 3.6 cm (1 7/16 in.) dia.

Power output
250 mW (at 10 % harmonic distortion)

Input
Microphone input jack (minijack) sensitivity 0.2 mV for 3 kilohms or lower impedance microphone

Output
Earphone jack (minijack) for 8 – 300 ohms earphone

Variable range of the tape speed

• From approx. +30% to –15% (with
• REC TIME switch at “NORMAL”)

Power requirements
3 V DC batteries R6 (AA) × 2/ External DC 3 V power sources

Dimensions (w/h/d) (incl. projecting parts and controls)
Approx. 112 × 36.6 × 90.3 mm (4 1⁄2 × 1 1⁄2 x 3 5⁄8 in.)

Mass
Approx. 175 g (6.2 oz.)

SPECIFICATIONS

Supplied accessories
The instructions in this manual are for 4 models. The TCM-20DV is the model used for illustration purposes.

Battery life (Approx. hours) (EIAJ*)

• Measured value by the standard of EIAJ (Electronic Industries Association of Japan). (Using a Sony HF series cassette tape and playing back with speakers)

Note

• The battery life may shorten depending on the operation of the unit.
• For maximum performance we recommend that you use alkaline batteries.

House Current
Connect the AC power adaptor to DC IN 3V and to a wall outlet. The AC power adaptor is supplied only with the TCM-22DV. For other models, use the AC-E30HG AC power adaptor (not supplied). Do not use any other AC power adaptor.

Note
Specifications for AC-E30HG vary for each area. Check your local voltage and the shape of the plug before purchasing. Design and specifications are subject to change without notice.

SERVICING NOTES

In this set, the S102 (POWER) detects REC/PLAYBACK on. It is mounted on the MAIN board, and therefore the REC/PLAYBACK on cannot be detected with the MAIN board removed. When making an operation check and voltage check of mechanical deck with the MAIN board removed, fix the S102 at turn on. MAIN BOARD (Conductor Side)

SAFETY-RELATED COMPONENT WARNING!!
COMPONENTS IDENTIFIED BY MARK 0 OR DOTTED LINE WITH MARK 0 ON THE SCHEMATIC DIAGRAMS AND IN THE PARTS LIST ARE CRITICAL TO SAFE OPERATION. REPLACE THESE COMPONENTS WITH SONY PARTS WHOSE PART NUMBERS APPEAR AS SHOWN IN THIS MANUAL OR IN SUPPLEMENTS PUBLISHED BY SONY.

Flexible Circuit Board Repairing

• Keep the temperature of the soldering iron around 270 °C during 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 damaged by heat.

GENERAL

Location of Controls

DISASSEMBLY

This set can be disassembled in the order shown below.

Note: Follow the disassembly procedure in the numerical order given.

CABINET (REAR), CASSETTE LID

MAIN BOARD, MECHANISM DECK (MT-20DV-118)

BELT

INSTALLATION MAIN BOARD

On installation MAIN board, adjust to the S101 and the S102.

MECHANICAL ADJUSTMENTS

1. Clean the following parts with a denatured-alcohol-moistened swab:
   • record/playback head pinch roller
   • erase head rubber belt
   • capstan idlers
2. Demagnetize the record/playback head with a head demagnetizer. (Do not bring the head demagnetizer close to the erase head.)
3. Do not use a magnetized screwdriver for the adjustments.
4. After the adjustments, apply suitable locking compound to the parts adjusted.
5. The adjustments should be performed with the rated power supply voltage (2.5 V) unless otherwise noted.

Torque Measurement

CQ-102C

| 2.16 – 4.7 mN•m (22 – 48 g•cm)

(0.31 – 0.67 oz•inch)

FWD

Back Tension

| 0.05 – 0.29 mN•m

(0.5 – 3 g•cm)

(0.007 – 0.04 oz•inch)

FF| ****

CQ-201B

| 4.90 mN•m (more than 50 g•cm)

(more than 0.69 oz•inch)

REW

Tape Tension Measurement

FWD

| ****

CQ-403C

| 4.90 mN•m (more than 50 g)

(more than 1.76 oz)

ELECTRICAL ADJUSTMENTS

Setting:

• Supplied voltage: 2.5 V
• Switch and control position
  • [VOL ] control (RV101) : mechanical center
  • [PAUSE ] switch (S105) : OFF
  • SPEED CONTROL: center click
  • [VOR] switch (S104) : OFF

Test Tape

• 0 dB=0.775 V

Record/Playback Head Azimuth Adjustment

Mode: playback

Procedure:

1. Turn the adjustment screw to obtain the maximum reading on level meter.
   Note: Several peaks may appear, but take the maximum.

2. After the adjustment, lock the adjustment screw with suitable locking compound.

Adjustment Location

Tape Speed Adjustment

Mode: playback

Procedure:
– Normal Speed –

1. Set [REC TIME] switch (S601) to NORMAL (4.8 cm/s) position, and playback the tape (WS-48A) .

2. Adjust RV601 so that frequency counter reading becomes 3,040 Hz.
   Specification values: 3,030 to 3,050 Hz – Double Speed –

3. Set [REC TIME] switch (S601) to DOUBLE (2.4 cm/s) position.

4. Playback the tape from the beginning for two minutes, then adjust RV603 so that frequency counter reading becomes 1,540 Hz.

Specification values: 1,535 to 1,545 Hz Confirm that deflection of the frequency counter reading between the beginning and the end of tape is within 1% (NORMAL: approx. 30.4 Hz, DOUBLE: approx. 15.4 Hz) .

Adjustment Location:

MAIN BOARD (Conductor Side)

DIAGRAMS

BLOCK DIAGRAM

PRINTED WIRING BOARDS

Note on Schematic Diagram:

• All capacitors are in μF unless otherwise noted. pF: μμF 50 WV or less are not indicated except for electrolytics and tantalums.

• All resistors are in Ω and 1/4 W or less unless otherwise specified.

• : panel designation.

• : B+ Line.

• : adjustment for repair.

• Total current is measured with no cassette installed.

• Power voltage is dc 3 V and fed with regulated dc power supply from external power voltage jack.

• Voltages are dc with respect to ground under no-signal conditions. no mark: PLAY

  <> : RECORD

• Voltages are taken with a VOM (Input impedance 10 MΩ). Voltage variations may be noted due to normal produc-tion tolerances.

• Signal path.
  : PLAY
  : RECORD

IC Block Diagram IC101 LA4168ML-TE-L

EXPLODED VIEWS

NOTE:

• XX and -X mean standardized parts, so they may have some difference from the original one.

• Color Indication of Appearance Parts Example:
  KNOB, BALANCE (WHITE) . . . (RED)
  ↑                     ↑
  Parts Color Cabinet’s Color

• Abbreviation 1E: No indication of country of origin

EXPLODED VIEWS

• Items marked “*” are not stocked since they are seldom required for routine service. Some delay should be anticipated when ordering these items.
• The mechanical parts with no reference number in the exploded views are not supplied.
• Accessories and packing materials are given in the last of the electrical parts list

CABINET SECTION

Ref. No.| Part No.| Description| Remark| Ref. No.| Part No.| Description| Remark
---|---|---|---|---|---|---|---
1| 3-318-382-31| SCREW (1.7), TAPPING| | 16| 3-924-739-01| SPRING, CASSETTE|
2

• 3

| 3-345-648-01

A-3021-314-A

| SCREW (M1.4), TOOTHED LOCK MAIN BOARD, COMPLETE| | 17

18

| X-4952-666-1 4-017-441-01| LID ASSY, CASSETTE CUSHION (B)|
4| 3-924-741-01| TERMINAL, PLUS| 19| 3-924-757-01| BRACKET (SPEAKER)
5| 3-936-973-01| TERMINAL, MINUS| 20| 3-328-319-01| STRAP, HAND
6| 3-924-744-01| SPRING (CLAW DETECTION), TENSION| 21| 3-924-749-21| LID, BATTERY CASE
7| 3-924-743-01| CLAW, ERASING PROTECTION| 22| 3-924-747-21| KNOB (PAUSE)
8| 3-334-565-41| SCREW (B1.7), TAPPING| 23| 3-019-597-11| CABINET (REAR)
9| 3-924-745-01| BAR, GROUND| 24| 3-318-203-92| SCREW (B1.7X9), TAPPING
10| 3-924-740-01| HOLDER, MICROPHONE| 25| 3-366-890-51| SCREW (IB LOCK)
11| 3-924-763-01| CUSHION (MICROPHONE)| 26| 3-831-441-99| CUSHION
12| 3-924-742-21| KNOB (VOR)| 28| 3-831-441-11| CUSHION, CABINET UPPER 10X7X0.5
13| 3-939-590-26| SCREW (IB LOCK)| 29| 1-676-967-11| SW BOARD
14| 3-578-101-31| PLATE, ORNAMENTAL| SP901| 1-505-838-11| SPEAKER (3.6cm)
15| 3-019-364-33| CABINET (FRONT) (20DV: 1E/23DV: 1E)| MIC101| 1-542-136-11| MICROPHONE, ELECTRET CONDENSER
15| 3-019-364-43| CABINET (FRONT) (20DV: 1E/23DV: 1E)| | |

MECHANISM DECK SECTION-1 (MT-20DV-118)

| | | | | |
---|---|---|---|---|---|---
| | | | | |
Ref. No.| Part No.| Description| Remark| | Ref. No.| Part No.| Description Remark
51| X-3377-250-1| LEVER, (2) ASSY, PINCH| | | 67| 3-924-674-01| SPRING (B. T), COMPRESSION
52| 3-925-146-01| BUTTON (FF) ( )| | | 68| 3-924-641-01| GEAR (T REEL)
53| 3-925-147-01| BUTTON (REW) ( )| | | 69| 3-924-726-01| SPRING (M GROUND), TORSION
54| 3-925-148-01| BUTTON (PLAY) ( )| | | 70| 3-907-943-01| BELT (CAPSTAN)
55| 3-925-145-01| BUTTON (REC) ( . )| | | 71| 3-925-109-01| CUSHION (MOTOR)
56| 3-924-738-01| BUTTON (STOP) ( )| | | 72| 3-925-108-01| SCREW (MOTOR)
57| 3-703-925-21| SCREW (M1.4)| | | 73| 3-924-644-01| SPRING (POWER TENSION), TENSION
58| 3-924-625-01| LEVER (HEAD)| | | 74| 3-348-160-11| SCREW (M1.4X1.6), PRECISION PAN
59| 3-924-645-01| BRACKET (HEAD)| | | 75| 3-927-754-11| CUSHION (M)
60| 3-924-685-01| SPRING (AZIMUTH), COMPRESSION| | | 76| 3-831-441-99| CUSHION
61| 3-704-197-91| SCREW (M1.4X1.8), LOCKING| | | 77| 3-030-766-12| SHEET (MOTOR)
62| 3-375-135-01| SCREW (1.4), SPECIAL| | | 78| 3-561-685-01| SHEET (C), INSULATING
63| 3-376-177-01| SCREW (M1.4X3.8)| | | HE901| 1-500-515-11| HEAD, MAGNETIC (ERASE)
64| 3-925-107-01| SPRING (IDLER), COMPRESSION| | | HRP901| 1-500-073-51| HEAD, MAGNETIC (RECORD/PLAYBACK)
65| 3-924-637-01| GEAR (FF)| | | M901| 1-763-453-21| MOTOR, DC (CAPSTAN/REEL) (WITH PULLEY)
66| 3-924-673-01| GEAR (S REEL)| | | | |

MECHANISM DECK SECTION-2 (MT-20DV-118)

Ref. No.| Part No.| Description| Remark| Ref. No.| Part No.| Description| Remark
---|---|---|---|---|---|---|---
101| 3-321-483-11| RING, RETAINING (0.25)| | 116| 3-924-633-01| SPRING (STOP), TENSION|
102| 3-315-495-31| WASHER| | 117| 3-924-622-01| LEVER (STOP)|
103| X-3370-384-1| FLYWHEEL ASSY| | 118| 3-924-643-01| SPRING (PR), TORSION|
104| 3-924-623-01| LEVER (PLAY)| | 119| 3-924-684-01| SPRING (LOCK PLATE), TENSION|
105| 3-924-621-01| LEVER (REW)| | 120| 3-924-619-01| LEVER (SW)|
106| 3-924-620-01| LEVER (FF)| | 121| 3-924-639-01| LEVER (CR)|
107| X-3370-388-1| TABLE ASSY, FELT| | 122| 3-924-618-01| LEVER (LOCK)|
108| 3-924-642-01| SPRING (FR), TORSION| | 123| 3-925-208-01| SPRING (REC), TENSION|
109| 3-924-629-01| LEVER (DETECTION)| | 124| 3-924-624-01| LEVER (REC)|
110| 3-925-207-01| SPRING (S. OFF), TENSION| | 125| X-3372-155-1| CHASSIS ASSY|
111| 3-924-630-01| LEVER (S.OFF)| | 126| 3-924-613-01| GEAR (FR)|
112| X-3370-387-1| LEVER ASSY, IDLER| | 127| 3-024-378-01| SPRING (FR LEVER), TORSION|
113| 3-924-682-01| BELT (FR)| | 128| 3-939-590-26| SCREW (IB LOCK)|
114| X-3370-385-1| PULLEY (FR) ASSY| | 129| 3-029-566-12| STOPPER (FF)|
115| 3-924-628-01| LEVER (FR)| | | | |

ELECTRICAL PARTS LIST

NOTE:

• Due to standardization, replacements in the parts list may be different from the parts speci-fied in the diagrams or the components used on the set.
• -XX and -X mean standardized parts, so they may have some difference from the original one.
• RESISTORS
  • All resistors are in ohms.
  • METAL: Metal-film resistor.
  • METAL OXIDE: Metal oxide-film resistor. F: nonflammable
• Abbreviation 1E: No indication of country of origin
• Items marked “*” are not stocked since they are seldom required for routine service. Some delay should be anticipated when order-ing these items.
• SEMICONDUCTORS In each case, u: µ, for example:
  • uA. . : μA. . uPA. . : μPA. .
  • uPB. . : μPB. . uPC. . : μPC. .
  • uPD. . : μPD. .
• CAPACITORS uF: μF
• COILS uH: μH

The components identified by mark 0 or dotted line with mark 0 are critical for safety. Replace only with part number specified. When indicating parts by reference number, please include the board.

RV101| 1-227-166-11| RES, VAR, CARBON (VOL )
RV601| 1-223-583-11| RES, ADJ, CARBON 1K
RV602| 1-225-598-11| RES, VAR, CARBON 2K (SPEED CONTROL)
RV603| 1-223-587-11| RES, ADJ, CARBON 22K
| | < SWITCH >
S101| 1-771-321-11| SWITCH, SLIDE (REC/PB)
S102| 1-572-688-11| SWITCH, PUSH (1 KEY) (POWER)
S104| 1-692-605-31| SWITCH, SLIDE (VOR)
S105| 1-572-922-11| SWITCH, SLIDE (PAUSE )

The components identified by mark 0 or dotted line with mark 0 are critical for safety. Replace only with part number specified.

Sony Corporation

• Personal Audio Division Company
• 2000B0579-1 Printed in Japan C 2000. 2 Published by General Engineering Dept.
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