Description of major IC .................................................. 1-13
COPYRIGHT
2001 JVC ASIA PTE LTD
No: 28208
DEC. 2001
RC-BX33SL
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 to 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 personnel 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 manufacture of responsibility for personal injury or property damage resulting
therefrom.
3. Many electrical 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 obtained by using replacement components rated for higher voltage, the Parts
List of Service Manual. Electrical components having such features are identified by shading on the
schematics and by () on the Parts List in the Service Manual. The use of a substitute replacement
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 temperature parts, moving parts and/or sharp edges for the prevention
of electric shock and fire hazard. When service is required, the original lead 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 metal 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 isolation 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 exposed 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 sensitivity in the following manner. Connect a 1,500
0.15µF 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 any exposed metal part
having a return path to the 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.).
0.15µF AC TYPE
1500
XL-SV320SL/SV305GD
XL-SV308BU
10W resistor paralleled by a
AC Voltmeter
(Having 1000
ohms/volts,
or more sensitivity
Place this
probe on
each exposed
10W
metal part.
Good earth ground
Warning
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. If 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.
1-2
RC-BX33SL
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 pickup). 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 (laser diode) in devices such as DVD players.
Be careful to use proper grounding in the area where repairs are being performed.
1.1.1. Ground 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 strap to release any static electricity built up in your body.
(caption)
Anti-static wrist strap
Conductive material
(conductive sheet) or
iron plate
1.1.3. Handling the optical pickup
1. In order to maintain quality during transport and before installation, both sides of the laser diode on the
replacement optical pickup are shorted. After replacement, return the shorted parts to their original
condition. (Refer to the text.)
2. Do not use a tester to check the condition of the laser diode in the optical pickup. The tester’s internal
power source can easily destroy the laser diode.
1.2. Handling the traverse unit (optical pickup)
1. Do not subject the traverse unit (optical pickup) to strong shocks, as it is a sensitive, complex unit.
2. Cut off the shorted part of the flexible cable using nippers, etc. after replacing the optical pickup. For specific details, refer to the replacement procedure in the text. Remove the anti-static pin when replacing the
traverse unit. Be careful not to take too long a time when attaching it to the connector.
3. Handle the flexible cable carefully as it may break when subjected to strong force.
4. It is not possible to adjust the semi-fixed resistor that adjusts the laser power. Do not turn it.
1-3
RC-BX33SL
Disassembly method
Removing the rear panel
1.
From behind the body, remove the Five screws
A
retaining the rear panel.
2.
Open the Battery door, then remove One Screw
B
retaining in the battery compartment
bottom side.
3
Then remove the Two screws
C
retaining the bottom of rear panel.
4
Take out the rear panel from the body. And disconnect the CN302 on the main board
right side.
Note:
Be careful of the FM antenna white wire, it is connection with the tuner PCB up side.
You can directly take out from the tuner PCB.
When you re-assembly the product, plug the FM antenna white wire into the Tuner
PCB'S "FM ANT" position.
Screw A.
Screw A.
Screw C.
Screw C.
Screw B.
1-4
RC-BX33SL
Removing the Main Board PCB (1)
1.
Open & remove the rear panel
2.
Remove the Two Screws
D
on the Black Backet,
then take out the black backet on the
front panel.
Screws D.
3
Remove the Two Screws
E
retaining on the
left of front panel.
Screws E.
4
Remove the One Screw
F
retaining on the
right of front panel.
Top panel
Screw F.
1-5
RC-BX33SL
Removing the Main Board PCB (2)
5
Disconnect the CN201, CN202 & C301 on the top of the
Main Board PCB.
Front Panel
CN 201
CN 202
Main PCB
CN 301
Top Panel
6
Then, take out the top panel from the front panel.
7
Remove the nine screws
G
from the Main Board PCB.
Screw G.
Screw G.
Screw G.
8
Take out the Main Board PCB from the front panel, & disconnect the CN901 & CN903
on the Main Board PCB.
1-6
RC-BX33SL
Adjustment method
Measurement instruments required for
Tuner section
adjustment
The input and output earth systems are separated.
1 Low frequency oscillator Reference measurement ----- 26.1mV(0.63/8)
This oscillator should have a capacity to outputoutput
0dB to 600 at an oscillation frequency ofInput positions ----- AM : Standard loop antenna
50Hz-20KHz FM : TP1 (hot) and TP2 (GND)
2 Electronic voltmeter
3 Distortion meterPrecautions for measurement
4 Frequency counter1 Direct connect to the IF sweeper output
5 Wow & flutter meterside and 1UF and 22 Kohm connect to the
6 Test tapesweeper input side. Same as FIG1.
TCC-112: Tape speed and running unevenness (3KHz)1 U
TCC-140: Reference level (1KHz)IC101TP16
TCC-182A: Head angle (8KHz), playback frequencyPIN1822 K
characteristics (1KHz) and dubbing
frequencyTP8
characteristics (125Hz and 8KHz)
7 Blank tape2 The IF sweeper output level should be made as
TYPE I : TDK-D60low as possible within the adjustable range.
3 Since the IF sweeper is a fixed device, there is
8 Torque gauge : For play and back tensionno to adjust this sweeper.
FWD(CT-120m), and FF/REW(CT-F)4 Since a ceramic oscillator is used, there is no
need to perform any MIX adjustment.
Measurement conditions5 Since a fixed coil is used, there is no need to
adjustment the FM tracking.
Power supply voltage -------------- AC120V (60Hz)6
Reference output -------------- Speaker : 0.63V/8In case of simultaneously measuring the voltage
Headphone : 0.245V/32in both of the input and output systmes with and
electronic voltmeter for two channels, therefore,
the earth should be connected particularly
Input for confirming recording and ------- CD : -10dBcarefully.
playback characteristics7 For connecting a dummy resistor when measuring
Measurement output terminal ------- Speaker CN301the output, use the wire with a greater code size.
* Load resistance -------------------------------------- 88 Whenever any mixed tape is used, use the band
pass filter (DV-12V).
Radio Input signal
AM frequency -------------------------------- 400Hz
AM modulation ---------------------------------- 30%
FM frequency --------------------------------- 1 KHz
FM frequency deviation ------------------ 22.5KHz
1-7
RC-BX33SL
TAPE DECK ADJUSTMENTS
1
HEAD AZIMUTH ADJUSTMET
2
AC BIAS FREQUENCY ADJUSTMENTS
3
TAPE SPEED ADJUSTMENT
Insert the test tape(MTT-111N,3,000 HZ)
CASSETTE MECHANISM SECTION
CASS DECK
P/R HEAD
( 1 ) Load the test tape TCC-182A 8KHz for azimuth
adjustment.
( 2 ) Press the PLAY button.
Use a cross-tip screwdriver to turn the screw for azimuth
( 3 ) 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.
( 1 ) Connect frequency counter to CN201(BS);
( 2 ) R/P swith in recording state;
( 3 ) Adjusting T201 use a plastic screwdriver, AC bias frepuency;62+-1KHZ..
( 1 )
( 2 ) Press the PLAY button.
( 3 ) Use a flat-tip screwdriver to turn the MOTOR VR
adjust MOTOR VR so that the frequency counter
become 3,000Hz
1-8
HEAD AZIMUTH ADJUSTING SCREW
RC-BX33SL
Tape recorder section
Items
ConfirmationTest tape1 Playback the test tape TCC-182A (8KHz)MaximumAdjust the head
of head angle:TCC-182A(8KHz)2 With the recording & playback mechanism, outputazimuth screw
ConfirmationTest tapeAdjust VR401 so that the frequency counterTape speed MOTOR VR
of tape speed:TCC-112(3KHz)reading becomes 3,010Hz +/-15Hz whenof deck
Measurement
conditionsValuespositions
Measurement output adjust the head azimuth screw so that theonly
terminal left and right output levers become
:Speaker terminal maximum, After adjustment, lock the
Sparker R head azimuth at least by half turn.
(Load resistance:8)
:Headphone terminal
Measurement outputplaying back the test tape TCC-112 (3KHz):3,010Hz
terminalwith playback and recording mechanism+/-15Hz
:Headphone terminalafter ending forward winding of the tape.
Measurement method
StandardAdjusting
Reference Values for Confirmation Items
ITEMS
Wow & flutterTest tapeWhen the test tape TCC-112 (3KHz) has been 0.25% or
Measurement
conditionsValuespositions
:TCC-112(3KHz)played back with the recording and playbackless
mechanism at the beginning of forward(WRMS)
Measurement outputwinding, the frequency counter reading of
terminalwow & flutter should be 0.25% or less
:Headphone terminal(WRMS).
Measurement method
StandardAdjusting]
1-9
RC-BX33SL
Electrical Performance
Reference Values for Electrical Function Confirmation Items
2 With the recording and playback
ITEMS
Adjustment of * Mode: PB mode1 With the recording and playback mechanism,
recording bias * Recording mode load the test tapes TDK-D60, and set the TDK-D60
current* Test tape: TDK-D60 mechanism to the recording and pausing4.5A
(Reference condition in advance . +/-0.5A
Value)* Measurement output
Adjustment of * Reference frequency 1 with the recording and playback mechanism,Output
recording and :1KHz and 8KHz load the test tapes (TDK-D60) and set thedeviation
playback (REF.:- 10dB) mechanism to the recording and pausingbetween
frequency* Test tape: TDK-D60 condition in advance.1KHz and
characteristics8KHz
Measurement
conditionsValuespositions
terminal2 After connecting 100ohms in series to the
:Both recording and recorder head, measure the bias current
headphone terminals with a valve voltmeter at both of the
terminals
* Measurement input2 While repetitively inputting the reference:-1dB +/-2dB
terminal: OSC IN frequency signal of 1KHz and 8KHz from
OSC IN, record and playback the tape.
Measurement method
StandardAdjusting
3 While receding and playback the test tape
Lch and Rch so that the output
deviation between 1KHz and 8KHz becomes
-1dB +/-2dB
Items
Recording* Playback1 While changing over to and form BIAS 162KHzT201
bias* Test tape: TDK-D60 and 2, confirm that the frequency is+/-6KHz
frequency changed
Measurement
conditionsValuespositions
* Measurement
terminal : BIAS TP on mechanism, load the test tape.
P.C. board (TDK-D60 ) , and set the
mechanism to the recording and pausing
condition in advance.
3 Confirm that the BIAS TP frequency on the
P.C. board is 62KHz +/-6KHz
Measurement method
StandardAdjusting]
1-10
Flow of functional operation until TOC read
Check that the voltage at the pin
focus A-curve amplitude
RC-BX33SL
Check Point
Power Key
Slider turns
REST SW ON.
17 of CN901 is OV (a moment)?
Automatic tuning
of TE offset
Laser ON
Check that the voltage at the
pin1 of IC902 + side is + 5V?
Detection of disc
Auto tuning of
Focus offset
Confirm that the Focus error
Auto. measurement of
s-cuve signal at the pin16 of
IC902 is approx.2V p-p
Confirm that the signal from
TE waveform at TOC readingpin14 IC902 is 0V as a
pin 25 of
IC601(TE)
Approx 3sec
Disc is rotated
accelerated pulse during
approx.400ms
Focus servo ON
VREF
Approx
1.8V
Trackin
g
servo
Tracking
servo on
statues
Disc to be
braked to
stop
(Tracking servo ON)
Auto. measurement of
Tracking error amplitude
Confirm the waveform of
the Tracking error signal
at the pin14 of IC902 (R926)
(See fig-1)
Disc status
to rotate
Auto
measurement
of TE amplitude
and auto tuning
of TE balance
TOC reading
finishes
500mV/div
2mS/div Fig.1
Automatic tuning of
Tracking error
Automatic tuning of
Automatic tuning of
Focus error gain
Automatic tuning of
Tracking error gain
TOC reading
Play a disc
Confirm the eys-pattern
at the lead of TP1
1-11
RC-BX33SL
TUNER ADJUSTMENTS
use a plastic screw driver for adjustments.
Adjust the intermediate frequency of AM and FM to the frequency of ceramic filter
Supply voltage : DC 12.0 V
Speaker impedance : 8 OHMS