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
µ
F
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
1
2
3
4
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
98
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
3
screws
(case 3 TP2)
4
case
1
BVTP 3x8
2
screws
(case 3 TP2
2-2. FRONT PANEL ASSY
!∞
front panel assy
0
BVTP 3x8
7
CN1002
!£
claw
1
CN311
2
CN621
8
CN1003
3
CN601
4
9
CN611
5
CN411
!¢
claw
BVTT 3x6
6
CN591
(WE425/WE525)
!¡
BVTP 3x8
!™
BVTP 3x8
– 5 –
2-3. CASSETTE LID ASSY (DECK A/B)
1
Push the EJECT button.
2
claws
3
cassette lid assy
2-4. MECHANISM DECK ASSY (DECK A/B)
3
mechanism deck assy
1
BVTP 2.6x8
– 6 –
2
BVTP 2.6x8
2-5. LEAF SW (A) BOARD (DECK A), LEAF SW (B) BOARD (DECK B)
1
PS 2.6x6
5
BVTT 2x4
7
LEAF SW (A) board
(Deck A)
LEAF SW (B) board
(Deck B)
claws
2
capstan motor assy
4
BVTT 2x4
a
3
wires
b
a
b
8
belt (capstan)
When installing,
pull the belt (capstan)
put around claws.
6
claws
– 7 –
2-6. PINCH LEVER (FWD) / (REV) ASSY (DECK A/B)
y
2
pinch lever (REV) assy
1
claw
4
pinch lever (FWD) assy
3
claw
2-7. FLYWHEEL (FWD) / (REV) ASSY (DECK A/B)
1
belt (FR2)
6
flywheel (REV) assy
7
washer
3
flywheel (FWD) ass
4
washer
2
stopper washer
5
stopper washer
– 8 –
2-8. MECHANICAL BLOCK ASSY (DECK A/B)
)
3
BVTT 2x3
4
mechanical block assy
5
reverse slider
2
BVTT 2x3
1
torsion spring
2-9. HEAD RELAY (PB) BOARD (DECK A), HEAD RELAY (REC) BOARD (DECK B)
3
tension spring (HEAD
4
head deck assy
2
HEAD RELAY (PB) board
(Deck A)
HEAD RELAY (REC) board
(Deck B)
1
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
47 k
LINE OUT
Ω
Ω
oscilloscope
VH
+
–+–
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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