JVC RC-W305 User manual

SERVICE MANUAL
RADIO CASSETTE RECORDER
RC-W305
No: 28223
SEP. 2005
COPYRIGHT ©2005 JVC ASIA PTE LTD
Area Suffix
U ----- Asia
UX ----- Middle East
SERVICE POLICY
No service part is available for this model.
Based on One to One exchange policy.
Contents
Safety Precaution...........................................................................2
Preventing Static Electricity...........................................................3
Disassembly Method......................................................................4
Adjustment Method.........................................................................5
Description Of Major IC................................................................8
Voltage Charts..............................................................................12
Wiring Connection Diagram........................................................13
Schematic Diagram ......................................................................14
Printed Circuit Board...................................................................15

XL-SV320SL/SV305GD
XL-SV308BU
2
RC-W305
1. This design of this product contains special hardware and many circuits and components specially for
safety purposes. For continued protection, no changes should be made ti the original design unless
authorised in writing by the manufacturer. Replacement parts must be identical to those used in the
original circuits. Services should be performed by qualified personel only.
2. Alterations of the design or circuitry of the product should not be made. Any design alterations of the
product should not be made. Any design alterations or additions will void the manufacturer's warranty
and will further relieve the manufacturer of responsibility for personal injury or property damage
resulting therefrom.
3. Many eletrical and mechanical parts in the products have special safety-related characteristics.
These characteristics are often not evident from visual inspection nor can the protection afforded by
them necessarily be obtain by using replaement components rated for higher voltage, the Parts
List of Service manual. Electrical components having such features ate identified by the shading on the
schematics and by (
! ) on the parts List in the Service Manual. The use of a substitute
repalcement which does not have the same safety characteristics as the recommended replacement
parts shown in the Parts List of Service manual may create shock, fire, or other hazards.
4. The leads in the products are routed and dressed with ties, clamps, tubing's, barriers and the like to
be separated from live parts, high temperatures parts, moving parts and/or sharp edges for the
prevention of electric shcok and fire hazard. When service is required, the original leat routing and
dress should be observed, and it should be confirmed that they have been returned to normal, after
re-assembling.
5. Leakage current check (Electrical Shock hazard testing)
After re-assembling the product, always perform an isolation check on the exposed metap Parts of the
product (antenna terminals, knobs, metal cabinet, screw heads, headphone jack, control shafts, etc.)
to be sure the product is safe to operate without danger of electrical shock.
Do not use a line isloation transformer during this check.
Plug the AC line cord directly into the AC outlet. Using a "Leakage Current Tester", measure the
leakage current from each ecposed metal parts of the cabinet, particularly and exposed metal
part having a return path to the chassis, to a known good earth ground. Any leakage current must
not exceed 0.5mA AC (r.m.s.)
Alternate check method
Plug the AC line cord directly into the AC outlet. Use an AC voltmeter having, 1,000 ohms per
volt or more sensitvity in the following manner. Connect a 1,500 ohm 10W resistor paralleled by a
0.15uF AC-type capacitor between an exposed
metal part and a known good earth ground.
Measure the AC voltage across the resistor with
the AC voltmeter.
Move the resistor connection to each exposed
metal part, particularly and exposed metal part
having a return path to te chassis and
measure the AC voltage across the resistor. Now,
reverse the plug in the AC outlet and repeat
each measurement. Voltage measured Any must
not exceed 0.75 V AC (r.m.s.). This corresponds
to 0.5 mA AC (r.m.s.).
1. This equipment has been designed and manufactured to meet international safety standards.
2. It is the legal responsibility of the repairer to ensure that these safety standards are maintained.
3. repairs must be made in accordance with the relevant safety standards.
4. It is essential that safety critical components are replaced by approved parts.
5. It mains voltage selector is provided, check setting for local voltage.
CAUTION
Burrs formed during moulding may be left over on some parts of the chassis. Therefore,
pay attention to such burrs in the case of performing repair of this system.
Safety Precautions
Warning

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Preventing static electricity
Electrostatic discharge (ESD), which occurs when static electricity stored in the body, fabric, etc. is discharged,
can destroy the laser diode in the traverse unit (optical pcikup). Take care to prevent this when performing repairs.
1.1. Grounding to prevent damage by static electricity
Static electricity in the work area can destroy the optical pickup in devicessuch.
Be careful to use proper grounding in the area where repairs are being performed.
1.1.1. Gound the workbench
1. Ground the workbench by laying conductive material (such as a conductive sheet) or an iron plate over
it before placing the traverse unit (optical pickup) on it.
1.1.2. Ground yourself
1. Use an anti-static wrist starp to release and static electricity built up in your body.

XL-SV320SL/SV305GD
XL-SV308BU
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

Disassembly Method
Remove the back cabinet
1, Open the battery cover and remove 2 screws inside it. (Screw A)
Screw A
2, Remove 5 screws on back side. (Screw B)
Screw B
Then the unit would be disassembled.

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

Adjustment Method
Instrument required Precautions for alignment
1 Direct connect to the IF sweeper output
1 Low frequency oscillator side and 1 UF and 22 Kohm connect to the
This oscillator should have a capacity to output sweeper input side . Same as FIG1 .
0dB to 600Өat an oscillation frequency of
50Hz-20KHz IC101
PIN18
2 Electronic voltmeter
3 Distortion meter
4 Frequency counter
5 Wow & flutter meter
6 Test tape 2 The IF sweeper output level should be made as
TCC-112 : Tape speed and running unevenness (3KHz) low as possible within the adjustable range .
TCC-140 : Reference level (1KHz) 3 Since the IF sweeper is a fixed device , there is no
TCC-182A : Head angle (8KHz) , playback frequency need to adjust this sweeper .
characteristics (1KHz) and dubbing frequency 4 Since a ceramic oscillator is used , there is no need
characteristics (125Hz and 8KHz) to perform any MIX adjustment .
5 Since a fixed coil is used , there is no need to
7 Blank tape adjust the FM tracking .
TYPE I : TDK-D60 6 The input and output earth systems are separated .
In case of simultaneously measuring the voltage in
8 Torque gauge : For play and back tension both of the input and output systems with an
FWD(CT-120m) , and FF/REW(CT-F) electronic voltmeter for two channels , therefore , the
earth should be connected particularly carefully .
General conditions 7 For connecting a dummy resistor when measuring
the output , use the wire with a greater code size .
Power supply voltage ------------- RC-S2055( U ) AC 110V/220V 60Hz/50 8 Whenever any mixed tape is used , use the band
Reference output -------------- Speaker : 0.63V/8Өpass filter (DV-12V)
Headphone : 0.245V/32Ө
playback characteristics
Measurement output terminal ---------- Speaker CN301
* Load resistance -------------------------------------- 8Ө
Tuner conditions
AM frequency -------------------------------- 400Hz
AM modulation ---------------------------------- 30%
FM frequency --------------------------------- 1 KHz
FM frequency deviation ------------------ 22.5KHz
Reference measurement ----- 26.1mV(0.63V/8Ө)
output
Input positions ----- AM : Standard loop antenna
FM : TP2 (hot) and TP3 (GND)
Reference measurement ----- 26.1mV(0.63V/8Ө)
output
Input positions ----- AM : Standard loop antenna
FM : TP2 (hot) and TP3 (GND)

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XL-SV308BU
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TUNER ADJUSTMENTS
Use a plastic screw driver for adjustments.
Adjust the intermediate frequency of AM and FM to the frequency of ceramic filter.
Set of unit
Supply voltage : DC 9.0V
Speaker impedance :8 ohms
Standard output : 50 mW
Function switch : RADIO
a. Parts Location
b. MW Adjustment Band switch : MW
Adjusting Connections SG Position of VTVM
Circuit lnput Output Frequency Tuning dial Oscilloscope
Connect sweep
1IF generator to IC101 455KHz Low T102
(18)PIN(A)
2Tuning Connect AM SG to Connect VTVM to 515 KHz Low end T104
3coverage loop ANT speaker terminals. 1640 KHz High end TC102
4Connect AM SG to Connect VTVM to 600 KHz 600 KHz MW ANT COIL
5loop ANT speaker terminals 1400 KHz 1400 KHz PVC101-C3
c. SW Adjustmen
t
Band switch : SW1 SW Dummy antenna : 75 ohms unbalance
Adjusting Connections SG Position of VTVM
Circuit lnput Output Frequency Tuning dial Oscilloscope
1Tuning Connect AM SG to Connect VTVM to 5.8 MHz Low end T105
2coverage FM ANT & D105(-) speaker terminals. 15.4 MHz High end TC103
3Connect AM SG to Connect VTVM to 7.0 MHz 7.0 MHz T107
4FM ANT &D105(-) speaker terminals. 12.0 MHz 16.0 MHz TC101
d. SW Adjustmen
t
Band switch : SW2 SW Dummy antenna : 75 ohms unbalance
Adjusting Connections SG Position of VTVM
Circuit lnput Output Frequency Tuning dial Oscilloscope
1Tuning Connect AM SG to Connect VTVM to 14.8 MHz Low end T106
2coverage FM ANT & D105(-) speaker terminals. 22.4 MHz High end TC104
3Connect AM SG to Connect VTVM to 15.0 MHz 15.0 MHz T108
4FM ANT &D105(-) speaker terminals. 22.0 MHz 22.0 MHz PVC101-C4
Step Adjustment
Connect AM sweep
generator to loop
ANT.
Max.
Max.
Tracking
Ste
p
Adjustmen
Tracking
Max.
Max.
TC102
TC103
TC104
T106
C1
T101
T107
C2
T105
T104
C4C3
L102 L103 T108TC101
T103T102
Ste
p
Adjustmen
Tracking
Max.
Max.

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e. FM Adjustment Band switch : FM FM Dummy antenna : 75 ohms unbalance
Adjusting Connection position of VTVM
Circuit Input Output tuning dial Oscilloscope
Connect sweep
1IF generator to IC101 10.7 MHz Low T101~T103
(18)PIN(A)
2Tuning Connect FM SG to Connect VTVM to 87.4 MHz Low end L103
3coverage FM ANT & D105(-) speaker terminals. 108.4 MHz High end PVC101-C1
4Connect FM SG to Connect VTVM to 90.0 MHz 90.0 MHz L102
5FM ANT &D105(-) speaker terminals. 106.0 MHz 106.0 MHz PVC101-C2
偩.TAPE DECK ADJUSTMENTS
1. HEAD REPLACEMENT
After replacement, demagnetize. the heads by using a degausser.
Be sure to clean the head before attempting to make any adjustments.
All wiring should be returned to the original position after work is completed.
2. HEAD AZIMUTH ADJUSTMENT
(1) Load the test tape(VTT-703, etc., 10 KHZ) for azimuth
adjustment.
(2) Press the PLAY button.
(3) Use a cross-tip screwdriver to turn the screw for azimuth
adjustment so that the left and right output are maximized
(4) Press the STOP button.
(5) After completion of the adjustment, use thread lock(TB-1401B)
to secure the azimuth-adjustment screw.
3. MOTOR SPEED ADJUSTMENT
(1) Insert the test tape(MTT-111N, etc., 3,000 HZ)
(2) Press the PLAY button.
(3) Use a flat-tip screwdriver to turn the SVR(located inside the
rear of the motor) to adjust SVR so that the frequency counter
become 3,000 HZ
4. CHECKING THE MECHANISM TORQUSE AND TENSION
Clean the head, capstan and pinch roller making any measurement.
Measurement Take-up torqe Back tension Tape tension
Drive-power cassette
Cassette ofr PLAY:TW-211A PLAY: TW-2111A
measurement F.FWD/REW:TW-2231 TW-2412
PLAY 30-60 gr.cm 2.0 - 4.5 gr. cm 60 gr or more
F.FWD 55-120 gr.cm ------ ------
REW 55-120 gr.cm ------ ------
Step SG Frequency
Tracking
Max.
Max.
Adjustment
Connect sweep
generator to
IC101(24)pin (B)

XL-SV320SL/SV305GD
XL-SV308BU
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RC-W305
LA1824 Block Diagram


Description of Major IC

RC-W305
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BA3308 Block Diagram

XL-SV320SL/SV305GD
XL-SV308BU
10
RC-W305
Block Diagram
BA3416BL

RC-W305
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XL-SV320SL/SV305GD
XL-SV308BU
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RC-W305


Voltage Charts
IC No.
Item 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
DC9V 0.04 1.31 3.04 4.37 4.37 0.00 4.37 0.10 2.84 1.30 1.30 0.17 4.37 3.65 3.66 1.22 1.22 1.26 1.39
Item 21 22 23 24
DC9V 4.34 4.34 0.00 0.29
IC No.
Item 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
DC9V 1.29 1.29 4.61 4.62 4.62 0.00 4.62 1.25 3.38 1.29 1.29 0.69 4.62 3.01 0.00 1.26 1.25 1.26 0.48
Item
21 22 23 24
DC9V 4.62 4.62 0.00 0.00
IC No.
Item 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
DC9V 1.29 1.29 4.59 4.61 4.61 0.00 4.61 1.23 3.35 1.29 1.29 0.55 4.61 3.00 0.00 1.26 1.25 1.26 0.40
Item 21 22 23 24
DC9V 4.61 4.61 0.00 0.00
IC No.
Item 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
DC9V 1.29 1.29 4.61 4.63 4.63 0.00 4.63 1.21 3.38 1.29 1.29 0.57 4.63 3.02 0.0 1.26 1.25 1.26 0.41
Item 21 22 23 24
DC9V 4.63 4.63 0.00 0.00
IC No.
Item 1 2 3 4 5 6 7 8 9 10 11 12
DC9V 10.03 5.12 9.20 1.19 0.00 10.03 0.00 0.00 1.19 9.18 5.13 10.16
IC No.
Item 1 2 3 4 5 6 7 8 9 10 11 12
DC9V 9.30 4.77 8.47 1.20 0.00 9.32 0.00 0.00 1.20 8.49 4.70 9.32
IC No.
Item 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
DC9V 0.99 0.00 0.00 0.00 2.16 2.14 5.50 1.87 5.13 1.07 0.00 1.31 0.59 0.59 0.00 0.00 0.00 0.00
IC No.
Item 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
DC9V 0.06 0.00 0.00 0.00 2.16 2.15 5.50 0.67 5.14 1.07 0.00 1.31 0.59 0.59 0.00 0.00 0.00 0.00
IC No.
Item 1 2 345 6 789
DC9V 0.95 0.00 0.92 0.46 0.00 0.00 0.90 0.00 0.89
IC No.
Item 1 2 345 6 789
DC9V 1.80 0.00 1.80 5.06 0.00 0.00 1.79 0.00 1.78
Transistor No.
Item EBCEBC
Votage(v) 6.10 6.80 9.35 6.10 6.80 9.05
IC303 LA-4227 CASS PLAY
IC301 BA3416 B CASS PLAY
IC302 BA3308 CASS REC
Q401 (CASS PLAY)
IC101 LA-1824 TUNER SW2
IC301 BA3416 A CASS PLAY
Q401 (TUNER)
IC101 LA-1824 TUNER FM
IC101 LA-1824 TUNER AM
IC101 LA-1824 TUNER SW1
IC303 LA-4227 TUNER
IC302 BA3308 CASS PLAY

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

Wiring Connections Diagram

XL-SV320SL/SV305GD
XL-SV308BU
14
RC-W305


Schematic Diagram

RC-W305
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

Printed Circuit Board

XL-SV320SL/SV305GD
XL-SV308BU
16
RC-W305

RC-W305
17

JVC Asia Pte Ltd
101 Thomson Road, #28-04 United Squares, Singapore 307591
(No: 28223) Printed in Singapore
200505(L)