Jvc RC-W305 Service Manual
SERVICE MANUAL
RADIO CASSETTE RECORDER
RC-W305
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
COPYRIGHT © 2005 JVC ASIA PTE LTD
No: 28223
SEP. 2005
RC-W305
CAUTION
Safety Precautions
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 (
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.
!
) on the parts List in the Service Manual. The use of a substitute
XL-SV320SL/SV305GD
XL-SV308BU
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.
Warning
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.
2
RC-W305
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.
3
RC-W305
Disassembly Method
Remove the back cabinet
1, Open the battery cover and remove 2 screws inside it. (Screw A)
XL-SV320SL/SV305GD
XL-SV308BU
Screw A
2, Remove 5 screws on back side. (Screw B)
Screw B
Then the unit would be disassembled.
4
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 600Ө at 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
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/8Ө
Headphone : 0.245V/32Ө
7 For connecting a dummy resistor when measuring
the output , use the wire with a greater code size .
pass filter (DV-12V)
RC-W305
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)
5
RC-W305
t
t
p
p
TUNER ADJUSTMENTS
Use a plastic screw driver for adjustments.
Adjust the intermediate frequency of AM and FM to th
Set of unit
Supply voltage : DC 9.0V
Speaker impedance :8 ohms
Standard output : 50 mW
Function switch : RADIO
a. Parts Location
TC102
TC103
TC104
T106
T105
T104
e frequency of ceramic filter.
T107
T108TC101
XL-SV320SL/SV305GD
XL-SV308BU
L102
L103
T101
T103T102
C4C3
b. MW Adjustment Band switch : MW
Step Adjustment
c. SW Adjustmen
Ste
Adjusting Connections
Circuit lnput Output
1 IF generator to IC101 455KHz Low T102
2
3
4
5
Connect AM sweep
generator to loop
ANT.
Tuning Connect AM SG to Connect VTVM to 515 KHz Low end T104
coverage loop ANT speaker terminals. 1640 KHz High end TC102
Tracking
Connect AM SG to Connect VTVM to 600 KHz 600 KHz MW ANT COIL
loop ANT speaker terminals 1400 KHz 1400 KHz PVC101-C3
Connect sweep
(18)PIN(A)
Band switch : SW1
Adjusting Connections
Circuit lnput Output
1 Tuning Connect AM SG to Connect VTVM to 5.8 MHz Low end T105
2 coverage FM ANT & D105(-) speaker terminals. 15.4 MHz High end TC103
3 Connect AM SG to Connect VTVM to 7.0 MHz 7.0 MHz T107
Tracking
4 FM ANT &D105(-) speaker terminals. 12.0 MHz 16.0 MHz TC101
SG
Frequency
SW Dummy antenna : 75 ohms unbalance
SG
Frequency
Position of VTVM
Tuning dial Oscilloscope
Position of VTVM
Tuning dial Os
C1
C2
Max.
Max.
cilloscope
Max.
Max.
d. SW Adjustmen
Ste
Adjusting Connections
Circuit lnput Output
1 Tuning Connect AM SG to Connect VTVM to 14.8 MHz Low end T106
2 coverage FM ANT & D105(-) speaker terminals. 22.4 MHz High end TC104
3 Connect AM SG to Connect VTVM to 15.0 MHz 15.0 MHz T108
Tracking
4 FM ANT &D105(-) speaker terminals. 22.0 MHz 22.0 MHz PVC101-C4
Band switch : SW2
SW Dummy antenna : 75 ohms unbalance
SG
Frequency
Position of VTVM
Tuning dial Os
cilloscope
Max.
Max.
6
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