Sony TC-WE425, TС-WE525, TС-WR681 Service Manual

TC-WE425/WE525/

WR681

SERVICE MANUAL

Photo: TC-WE425

Dolby noise reduction extension manufactured under license from Dolby Laboratories Licensing Corporation. HX Pro originated by Bang & Olufsen. “DOLBY”, the double-D symbol a and “HX PRO” are trademarks of Dolby Laboratories Licensing Corporation.

US Model

TC-WE425/WR681

Canadian Model

TC-WE425

AEP Model

TC-WE525/WR681

UK Model

TC-WE525

E Model

Australian Model

TC-WE425/WR681

Chinese Model

TC-WE425

Model Name Using Similar Mechanism Tape Transport DECK A TCM-230ASR1 Mechanism Type DECK B TCM-230ASR2

NEW

System

Recording system

4-track 2-channel stereo

Fast-winding time (approx.)

100 sec. (with Sony C-60 cassette)

Bias

AC bias

Signal-to-noise ratio (at peak level and weighted with Dolby NR off)

Type I tape, Sony Type I (NORMAL): 55 dB Type II tape, Sony Type II (HIGH): 57 dB Type IV tape, Sony Type IV (METAL): 58 dB

S/N ratio improvement (approximate values)

With Dolby B NR on: 5 dB at 1 kHz, 10 dB at 5 kHz With Dolby C NR on: 15 dB at 500 Hz, 20 dB at 1 kHz

Harmonic distortion

0.4% (with Type I tape, Sony Type I (NORMAL): 160 nWb/m 315 Hz, 3rd H.D.)

1.8% (with Type IV tape, Sony Type IV (METAL): 250 nWb/m 315 Hz, 3rd H.D.)

SPECIFICATIONS

Frequency response (Dolby NR off) Tape type

Type I tape, Sony Type I 30-16,000 Hz (±3 dB, IEC), (NORMAL) 20-17,000 Hz (±6 dB)

Type II tape, Sony Type II 30-17,000 Hz (±3 dB, IEC), (HIGH) 20-18,000 Hz (±6 dB)

Type IV tape, Sony Type IV 30-19,000 Hz (±3 dB, IEC), (METAL) 20-20,000 Hz (±6 dB),

Wow and flutter

± 0.15% W. Peak (IEC)

0.1% W. RMS (NAB) ± 0.2% W. Peak (DIN)

– Continued on next page –

MICROFILM

STEREO CASSETTE DECK

– 1 –

Inputs

Line inputs (phono jacks)

Sensitivity : 0.16 V Input impedance : 47 kilohms

Outputs

Line outputs (phono jacks)

Rated output level : 0.5 V at a load impedance of 47 kilohms Load impedance : Over 10 kilohms

Headphones (stereo phono jack) (TC-WE425/WE525 only)

Output level : 0.25 mW at a load impedance of 32 ohms

General

Power requirements Where purchased Power requirements

US, Canadian 120 V AC, 60 Hz

AEP, UK, Chinese 220 - 230 V AC, 50/60 Hz

Australian 240 V AC, 50/60 Hz

E, Singapore, Malaysia 120/220/230 - 240 V AC, 50/60 Hz

Power consumption

18 W

Dimensions (approx.) (w/h/d)

430 × 120 × 290 mm (w/h/d) (17 × 4 3/4 × 11 3/8 in.) including projecting parts and controls

Mass (approx.)

4 kg (8 lbs 13 oz)

SAFETY CHECK-OUT

After correcting the original service problem, perform the following safety check before releasing the set to the customer: Check the antenna terminals, metal trim, “metallized” knobs, screws, and all other exposed metal parts for AC leakage. Check leakage as described below.

LEAKAGE TEST

The AC leakage from any exposed metal part to earth ground and from all exposed metal parts to any exposed metal part having a return to chassis, must not exceed 0.5 mA (500 microampers). Leakage current can be measured by any one of three methods.

1. A commercial leakage tester, such as the Simpson 229 or RCA WT-540A. Follow the manufacturers’ instructions to use these instruments.

2. A battery-operated AC milliammeter. The Data Precision 245 digital multimeter is suitable for this job.

3. Measuring the voltage drop across a resistor by means of a V OM or battery-operated A C v oltmeter. The “limit” indication is 0.75 V, so analog meters must have an accurate low-voltage scale. The Simpson 250 and Sanwa SH-63Trd are examples of a passive VOM that is suitable. Nearly all battery operated digital multimeters that have a 2V AC range are suitable. (See Fig. A)

To Exposed Metal Parts on Set

Supplied accessories

Audio connecting cords (2 phono plugs - 2 phono plugs) (2) CONTROL A1 cord (supplied for Canadian models only) (1)

Design and specifications are subject to change without notice.

SAFETY-RELATED COMPONENT WARNING!!

COMPONENTS IDENTIFIED BY MARK ! OR DOTTED LINE WITH MARK ! ON THE SCHEMATIC DIAGRAMS AND IN THE PARTS LIST ARE CRITICAL TO SAFE OPERATION. REPLACE THESE COMPONENTS WITH SONY P AR TS WHOSE P AR T NUMBERS APPEAR AS SHO WN IN THIS MANU AL OR IN SUPPLEMENTS PUBLISHED BY SONY.

0.15

1.5k

Ω

Earth Ground

AC voltmeter (0.75V)

Fig. A. Using an AC voltmeter to check AC leakage.

ATTENTION AU COMPOSANT AYANT RAPPORT

LES COMPOSANTS IDENTIFIÉS P AR UNE MARQUE ! SUR LES DIAGRAMMES SCHÉMA TIQUES ET LA LISTE DES PIÈCES SONT CRITIQUES POUR LA SÉCURITÉ DE FONCTIONNEMENT. NE REMPLACER CES COMPOSANTS QUE PAR DES PIÈCES SONY DONT LES NUMÉROS SONT DONNÉS DANS CE MANUEL OU DANS LES SUPPLÉMENTS PUBLIÉS PAR SONY.

À LA SÉCURITÉ!!

– 2 –

MODEL IDENTIFICATION

TABLE OF CONTENTS

–Back panel–

Part No. Model 3-021-244-0π TC-WE425 : US model 3-021-244-1π TC-WE425 : CND model 3-021-244-2π TC-WE525 : AEP model 3-021-244-3π TC-WE525 : UK model 3-021-244-4π TC-WE425 : AUS model 3-021-244-5π TC-WE425 : SP, MY model 3-021-244-6π TC-WE425 : CH model 3-021-245-0π TC-WR681 : US model 3-021-245-1π TC-WR681 : AEP model 3-021-245-2π TC-WR681 : E model 3-021-245-3π TC-WR681 : AUS model 3-021-245-4π TC-WR681 : SP model

• Abbreviation CND : Canadian model AUS : Austrarian model SP : Singapore model MY : Malaysia model CH : Chinese model

Part No.

1. GENERAL

1-1. Location of Controls ........................................................... 4

2. DISASSEMBLY

2-1. Case ..................................................................................... 5

2-2. Front Panel Assy ................................................................. 5

2-3. Cassette Lid Assy (Deck A/B) ............................................ 6

2-4. Mechanism Deck Assy (Deck A/B) ....................................6

2-5. Leaf SW (A) board (Deck A),

Leaf SW (B) board (Deck B) .............................................. 7

2-6. Pinch Lever (FWD)/(REV) Assy (Deck A/B)..................... 8

2-7. Flywheel (FWD)/(REV) Assy (Deck A/B) ......................... 8

2-8. Mechanical Block Assy (Deck A/B) ................................... 9

2-9. Head Relay (PB) Board (Deck A),

Head Relay (REC) Board (Deck B) .................................... 9

3. MECHANICAL ADJUSTMENTS...............................10

4. ELECTRICAL ADJUSTMENTS................................. 10

5. DIAGRAMS

5-1. IC Pin Description............................................................. 14

5-2. Circuit Boards Location .................................................... 16

5-3. Printed Wiring Boards –Main Section– ............................ 17

5-4. Schematic Diagram –Main Section (1/3)– ........................ 19

5-5. Schematic Diagram –Main Section (2/3)– ........................ 21

5-6. Schematic Diagram –Main Section (3/3)– ........................ 23

5-7. Printed Wiring Boards –Panel Section– ............................ 25

5-8. Schematic Diagram –Panel Section– ................................ 27

5-9. Printed Wiring Boards –Power Section–........................... 29

5-10. Schematic Diagram –Power Section– ............................... 31

5-11. Printed Wiring Boar d –Deck A Section–........................... 32

5-12. Schematic Diagram –Deck A Section– ............................. 32

5-13. Printed Wiring Board –Deck B Section– .......................... 33

5-14. Schematic Diagram –Deck B Section– ............................. 33

6. EXPLODED VIEWS

6-1. Case Section ...................................................................... 34

6-2. Chassis Section ................................................................. 35

6-3. Cassette Holder Section ....................................................36

6-4. Front Panel Section ........................................................... 37

6-5. Tape Mechanism Section .................................................. 38

7. ELECTRICAL PARTS LIST ........................................ 39

– 3 –

1-1. LOCATION OF CONTROLS

SECTION 1

GENERAL

567

2 3

10 1312 1411 15

1. 1/u (Power) button (US, Canadian) U (Power) button (EXCEPT US, Canadian)

2. DIRECTION MODE switch

3. PITCH CONTROL (Ø ON/ø OFF) switch (TC-WE525)

4. PITCH CONTROL knob (TC-WE525)

5. Cassette holder (Deck A)

6. COUNTER A buttons (Deck A) RESET button MEMORY button

7. Display window

8. COUNTER B buttons (Deck B) RESET button MEMORY button

9. Cassette holder (Deck B)

10. Tape operation buttons (Deck A)

0 (REW) button ) (FF) button

p CLEAR (Stop) button

ª (Reverse play) button

· (Foward play) button

21 20 19

18 17 16

11. § (Eject) button (Deck A)

12. DOLBY NR switch

13. Tape operation buttons (Deck B)

0 (REW) button ) (FF) button

p (Stop) button

ª (Reverse play) button

· (Foward play) button P PAUSE button R REC MUTING button r REC button

14. § (Eject) button (Deck B)

15. START (DECK B P) button HIGH/NORMAL, DUBBING AnB button

16. PHONES jack (TC-WE425/WE525)

17. SYNCHRO button and indicator (TC-WE425/WE525)

18. ARL button

19. FADER button

20. REC LEVEL knob

21. AUTO indicator

– 4 –

SECTION 2

)

DISASSEMBLY

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

2-1. CASE

screws

(case 3 TP2)

case

BVTP 3x8

screws

(case 3 TP2

2-2. FRONT PANEL ASSY

!∞

front panel assy

BVTP 3x8

CN1002

!£

claw

CN311

CN621

CN1003

CN601

CN611

CN411

!¢

claw

BVTT 3x6

CN591

(WE425/WE525)

!¡

BVTP 3x8

!™

BVTP 3x8

– 5 –

2-3. CASSETTE LID ASSY (DECK A/B)

Push the EJECT button.

claws

cassette lid assy

2-4. MECHANISM DECK ASSY (DECK A/B)

mechanism deck assy

BVTP 2.6x8

– 6 –

BVTP 2.6x8

2-5. LEAF SW (A) BOARD (DECK A), LEAF SW (B) BOARD (DECK B)

PS 2.6x6

BVTT 2x4

LEAF SW (A) board (Deck A) LEAF SW (B) board (Deck B)

claws

capstan motor assy

BVTT 2x4

wires

belt (capstan)

When installing, pull the belt (capstan) put around claws.

claws

– 7 –

2-6. PINCH LEVER (FWD) / (REV) ASSY (DECK A/B)

pinch lever (REV) assy

claw

pinch lever (FWD) assy

claw

2-7. FLYWHEEL (FWD) / (REV) ASSY (DECK A/B)

belt (FR2)

flywheel (REV) assy

washer

flywheel (FWD) ass

washer

stopper washer

– 8 –

2-8. MECHANICAL BLOCK ASSY (DECK A/B)

)

BVTT 2x3

mechanical block assy

reverse slider

BVTT 2x3

torsion spring

2-9. HEAD RELAY (PB) BOARD (DECK A), HEAD RELAY (REC) BOARD (DECK B)

tension spring (HEAD

head deck assy

HEAD RELAY (PB) board (Deck A) HEAD RELAY (REC) board (Deck B)

BVTT 2x4

– 9 –

SECTION 3

MECHANICAL ADJUSTMENTS

SECTION 4

ELECTRICAL ADJUSTMENTS

PRECAUTION

1. Clean the following parts with a denatured alcohol-moistened swab :

record/playback/erase head pinch roller rubber belts capstan idlers

2. Demagnetize the record/playback head with a head demagnetizer.

3. Do not use a magnetized screwdriver for the adjustment.

4. After the adjustments, apply suitable locking compound to the parts adjusted.

5. The adjustments should be performed with the rated power supply voltage unless otherwise noted.

Torque Measurement

Mode Torque meter Meter reading

Forward CQ-102C

Forward (0.014 to 0.083 oz • inch) back CQ-102C tension DECK B : 2 to 9 g • cm

Reverse CQ-102RC

Reverse back CQ-102RC tension

FF/REW CQ-201B

30 to 65 g • cm

(0.42 to 0.90 oz • inch)

DECK A : 1 to 6 g • cm

(0.028 to 0.125 oz • inch)

30 to 65 g • cm

(0.42 to 0.90 oz • inch)

1 to 6 g • cm

(0.014 to 0.083 oz • inch)

70 to 120 g • cm

(0.97 to 1.67 oz • inch)

PRECAUTION

1. The adjustment should be performed in the publication. (Be sure to male playback adjustment at first.)

2. The adjustments and measurement should be performed for both L-CH and R-CH.

• Switch position

DOLBY NR switch : OFF DIRECTION MODE switch : A

• Standard record position :

Deliver the standard input signal level to input jack and set the REC LEVEL control to obtain the standard output signal level as follows.

– Record Mode–

AF OSC

10 k

600

Ω

LINE IN

Ω

set

attenuator

Standard Input Level

Input terminal LINE IN

source impedance 10 kΩ

input signal level 0.5 V (–3.8 dB)

Standard Output Level

Output terminal LINE OUT

load impedance 47 kΩ

output signal level 0.5 V (–3.8 dB)

level meter

47 k

Ω

LINE OUT

+ –

Test Tape

T ape Contents Use

P-4-A100 10 kHz, –10 dB Azimuth Adjustment WS-48B 3 kHz, 0 dB Tape Speed Adjustment P-4-L300 315 Hz, 0 dB PB Level Adjustment

0 dB = 0.775 V

Test Mode

1. Turn ON power switch pressing “REC MUTING” and “)”

(FF) (DECK A) at the same time. At first, all the fluorescent indicator light up, then the system returns to normal display. (Ho we ver, “0. 00” is not displayed on the counter.)

2. To release the test mode, turn OFF the power switch.

– 10 –

Record/Playback Head Azimuth Adjustment

DECK A DECK B

Procedure:

1. Forward Playback Mode

test tape P-4-A100 (10 kHz, –10 dB)

set

LINE OUT

47 k

level meter

Ω

+ –

2. Turn the adjustment screw for the maximum output levels. If these levels do not match, turn the adjustment screw until both of output levels match together within 1 dB.

L-CH peak

screw position

R-CH peak

output level

1 dB

L-CH peak

R-CH peak

within 1 dB

screw position

within

3. Playback Mode

test tape P-4-A100 (10 kHz, –10 dB)

L-CH

set

R-CH

Screen Pattern

47 k

LINE OUT

Ω

oscilloscope

–+–

T ape Speed Adjustment DECK A DECK B

Procedure:

–Forward Playback Mode–

test tape WS-48B (3 kHz, 0 dB)

set

LINE OUT

frequency counter

47 k

Ω

+ –

(High speed adjustment)

1. Set to test mode. (Refer to page 10.)

2. Set to FWD playback mode.

3. Twice pressing the HIGH/NORMAL switch.

4. Adjust RV316 (DECK A), RV416 (DECK B) so that the

frequency counter reading becomes 5,980 ± 20 Hz.

5. Release test mode after adjustment is completed. (Normal speed adjustment)

1. Set to FWD playback mode.

2. Adjust RV317 (DECK A), RV417 (DECK B) so that the

frequency counter reading becomes 3,000 ± 10 Hz.

(Pitch control adjustment) (DECK A) (TC-WE525 only)

1. Push the PITCH CONTROL switch.

2. Set RV986 (PITCH CONTROL knob) to mechanical center.

3. Set to FWD playback mode.

4. Adjust RV318 so that the frequency counter reading becomes

2,990 ± 10 Hz.

Frequency difference between the beginning and the end of the tape should be within ± 3%. Frequency difference between the deck A and deck B the beginning of the tape should be within ± 1.5%.

Adjustment Location: MAIN board (See page 13.)

Playback Level Adjustment DECK A DECK B

Procedure:

–Forward Playback Mode–

test tape P-4-L300 (315 Hz, 0 dB)

47 k

level meter

Ω

In phase 45˚ 90˚ 135˚ 180˚

good wrong

4. Change the reverse playback mode and repeat the steps 1 to 3.

5. After the adjustment, lock the adjustment screws with suitable locking compound.

Adjustment Location: –record/playback head–

forward side

adjustment screws

reverse side

set

LINE OUT

Adjust DECK A : RV111 (L-CH), RV211 (R-CH) and DECK B : R V121 (L-CH), RV221 (R-CH) so the level meter reading becomes the adjustment limits below.

Adjustment V alue:

LINE OUT level : –7.7 ± 0.5 dB (0.301 to 0.338 V)

Level difference between channels : within 0.5 dB

Confirm that the LINE OUT level does not change in playback mode while changing the mode from playback to stop several times.

Adjustment Location: MAIN board (See page 13.)

– 11 –

+ –

Bias Consumption Current Adjustment DECK B

This adjustment should be performed when replacing the head assy or the bias oscillator transformer (T131, T231).

Procedure:

digital voltmeter

+ –

TP431

LINE IN no signal

blank tape CS-413

set

L-CHR-CH

321

1. Connect the digital voltmeter to test point TP431.

2. Set RV131 (L-CH), RV231 (R-CH) to mechanical center.

3. Set to FWD record mode.

4. Adjust T131 (L-CH), T231 (R-CH) so that the digital voltmeter reading becomes minimum.

Record Level Adjustment DECK B

Setting:

REC LEVEL control : standard record position (See page 10.)

Procedure:

1. Record Mode

AF OSC

attenuator

10 k

Ω

set

600

Ω

LINE IN

315 Hz, 38.8 mV (–26 dB)

blank tape CS-123

2. Playback Mode

recorded portion

47 k

level meter

Ω

Adjustment V alue: Maximum 220 mV

Adjustment Location: MAIN board (See page 13.)

Record Bias Adjustment DECK B

Setting:

REC LEVEL control : standard record position (See page 10.)

Procedure:

1. Record Mode

AF OSC

attenuator

10 k

600

Ω

LINE IN

1) 315 Hz

2) 10 kHz

Ω

set

38.8 mV (–26 dB)

blank tape CS-123

2. Playback Mode

recorded portion

set

47 k

level meter

Ω

+ –

set

LINE OUT

+ –

Confirm playback the tape recorded become adjustment level as follows. If necessary, adjust RV161 (L-CH), RV261 (R-CH) and repeat the steps 1 and 2.

Adjustment V alue:

LINE OUT level : –26 ± 0.5 dB (36.7 to 41.1 mV)

Adjustment Location: MAIN board (See page 13.)

LINE OUT

Confirm that the 10 kHz playback output is 0 ± 0.5 dB relative to the 315 Hz output. If necessary, adjust RV131 (L-CH), RV231 (RCH) and repeat the steps given above.

Adjustment Location: MAIN board (See page 13.)

– 12 –

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