Vitek VT-3451 SERVICE MANUAL
CAUTION: Before servicing the chassis, read the "Important Service safety Information"
section on page 2 of this manual.
ANALOG TUNING RADIO WITH MP3/CD PLAYER
SPECIFICATIONS CONTENTS
AM/FM TUNER SECTION
ANTENNA SYSTEM
TUNING RANGE
INTERMEDIATE FREQUENCY
AUDIO SECTION
SPEAKER IMPEDANCE
GENERAL
POWER INPUT
AC POWER CONSUMPTION
AM: FERRITE BAR
FM: TELESCOPIC
AM: 540~1600KHz
FM: 64~108MHz
AM: 465KHz +/-5KHz
FM: 10.7MHz +/-0.1MHZ
8 ohms
AC 230V, 50Hz
2x1.2W/CHANNEL @10%THD
IMPORTANT SERVICE SAFETY INFORMATION
DISASSEMBLY INSTRUCTIONS
ALIGNMENT PROCEDURES
LOCATION OF CONTROLS
BLOCK DIAGRAM
WIRING DIAGRAM
IC BLOCK DIAGRAM
PRINTED CIRCUIT BOARDS
SCHEMATIC DIAGRAMS
EXPLODED VIEW
EXPLODED PARTS LIST
REPLACEMENT PARTS LIST
2
3
4
5
6
7
8-10
11-13
14-15
16
17
18-22
IMPORTANT SERVICE SAFETY INFORMATION
1.
SAFETY PRECAUTIONS
Before returning a unit to the customer, always make a safety check of
the entire unit, including, but not limited to the following items:
a. Be sure that no built-in protective devices are defective and/or have
been defeated during servicing.
(1)
Protective shields are provided to protect both the technician and
the customer. Correctly replace all missing protective shields
including any removed for servicing convenience.
(2)
When reinstalling the chassis and/or other assemblies in the
cabinet, be sure t put back in place all protective devices, including,
but not limited to, nonmetallic control knobs, insulating fishpapers,
adjustment and compartment covers/shields and isolation resistor/
capacitor networks. Do not operate this unit or permit it to be
operated without all protective devices correctly installed and
functioning.
b.
Be sure that there are no cabinet openings through which an adult or
child might be able to insert their fingers and contact a hazardous
voltage. such openings include, but are not limited to, excessively wide
cabinet ventilation slots, and an improperly fitted and/or incorrectly
secured cabinet back cover.
c.
Leakage Current Hot Check - With the unit completely reassembled,
plug the AC line cord directly into a 120V AC outlet. (Do not use an
isolation transformer during this test.) Use a leakage current tester or a
metering system that complies with American National Standards
institute (ANSI) C101.1”Leakage current for Appliances” and
Underwriters laboratories (UL) 1410,(50.7). With the unit AC switch first
in the ON position and then in the OFF position, measure from a known
earth ground (metal water pipe, conduit, etc.), especially any exposed
metal parts that offer an electrical return path to the chassis. Any
current measured must not exceed 0.5 milliamp. Reverse the unit power
cord plug in the outlet and repeat test. ANY MEASUREMENTS NOT
WITHIN THE LIMITS SPECIFIED HERENIN INDICATE A POTENTIAL
SHOCK HAZARD THAT MUST BE ELIMINATED BEFORE
RETURNING THE UNIT TO THE CUSTOMER.
(READING SHOULD
NOT BE ABOVE
0.5mA)
AC Leakage Test
DEVICE
UNDER
TEST
2-WIRE CORD
ALSO TEST WITH
PLUG REVERSED
(USING AC ADAPTER
PLUG AS REQUIRED)
d.
Insulation Resistance Test Cold Check
Unplug the power supply cord and connect a jumper wire between the
two prongs of the plug.
Turn on the power switch of the unit.
Measure the resistance with an ohmmeter between the jumpered AC
plug and each exposed metallic cabinet part on the unit, such as
screwheads, antenna, control shafts, handle brackets, etc. When the
exposed metallic part has a return path to the chassis, the reading
should be between 1 and 5.2 megohms. When there is no return path to
the chassis, the reading must be “infinite”. If it is not within the limits
specified, there is the possibility of a shock hazard, and the unit must be
repaired and rechecked before it is returned to the customer.
TEST ALL
EXPOSED METAL
SURFACES
+
LEAKAGE
CURRENT
TESTER
EARTH
GROUND
ANTENNA
TERMINAL
EXPOSED
METAL
PART
2.
PRODUCT SAFETY NOTICE
OM
OHMMETER
Some electrical and mechanical parts have special safety related
characteristics which are often not evident from visual inspection, nor
can the protection they give necessarily be obtained by replacing them
with components rated for higher voltage, wattage, etc. Parts that
have special safety characteristics are identified by a on
schematic and parts list. Use of a substitute replacement that does not
have the same safety characteristics as the recommended
replacement part might create shock, fire, and/or other hazards.
Product safety is under review continuously and new instructions are
issued whenever appropriate.
SERVICING PRECAUTIONS
3.
CAUTION”Before servicing the unit covered by this service manual
and its supplements read and follow the SAFETY PRECAUTIONS on
this page. NOTE”If unforeseen circumstances create a conflit
between the following servicing precautions and any of the safety
precautions, always follow the safety precautions. Remember: Safety
First.
General Servicing Precautions.
a. Always unplug the unit’s AC power cord from the AC power
source before:
(1) removing or reinstalling any component, circuit board, module, or
any other unit assembly.
(2) disconnecting or reconnecting any unit electrical plug or other
electrical connection.
(3) connecting a test substitute in parallel with an electrolytic
capacitor in the unit.
Caution: A wrong part substitution or incorrect polarity installation
of electrolytic capacitors may result in an explosion
hazard.
b. Do not defeat any plug/socket B+ voltage interlocks with which
the unit covered by this service manual might be equipped.
c. Do not apply AC power to this unit and/or any of its electrical
assemblies unless all solid-state device heat sinks are correctly
installed.
d. always connect a test unit instrument’s ground lead to the unit’s
chassis ground before connecting the test instrument’s positive
lead. Always remove the test instrument’s ground lead last.
LASER PRECAUTIONS
4.
WARNING!!
When servicing, (in case it is necessary to confirm Laser Beam
1.
Emission) be sure not to place your eyes any closer than 1 ft or
30cm from the surface of the Objective Lens on the Opticval
Pickup Block.
HANDLING THE LASER PICKUP
2.
Laser diodes are extremely susceptible to damage from static
electricity. Even if a static discharge does not ruin the diode, it can
shorten its life or cause it to work improperly. When replacing the
pickup, use a conductive mat on the floor and desk and wear a
wrist band connected to ground through a 1M ohm resistor to
protect the laser diode from static damage. If the lens should get
dusty, blow off the dust carefully from the object.
3.
There are no adjustable parts in the pickup assembly. If it is
defective, replace the whole pickup assembly.
CAUTION:
USE OF CONTROLS, ADJUSTMENTS OR PERFORMANCE OF
PROCEDURES HEREIN MAY RESULT IN HAZARDOUS
RADIATION EXPOSURE.
DANGER:
IF INTERLOCK FAILS OR IS DEFEATED, THE LASER LIGHT IS
ABLE TO FUNCTION. THE LASER IS INVISIBLE, AVOID DIRECT
EXPOSURE TO BEAM.
2
DISASSEMBLY INSTRUCTIONS
1) ROTATE THE UNIT TO EXPOSE THE BACK SIDE.
2) REMOVE THE 8 SCREWS AS SHOWN IN FIG.1.
FIG.1
3
ALIGNMENT PROCEDURES
AM I.F. ALIGNMENT
1. Set the FUNCTION SELECTOR SWITCH to RADIO & AM BAND.
2. Connect a SWEEPSCOPE OUTPUT to AM antenna terminal.
3. Connect a SWEEPSCOPE INPUT to pin16 or 17 of IC001 through a 1uf capacitor and ground.
STEP SET SIGNAL SET DIAL ADJUST ADJUST FOR
1 465KHz GANG OPEN CF502(AM IF)
AM R.F. ALIGNMENT
1. Connect an RF generator to a standard radiatin g lo op.
2. Connect a SCOPE and VTVM across the speaker output.
STEP SET SIGNAL SET DIAL ADJUST ADJUST FOR
1 540KHz T503 (AM OSC COIL)
2 1600KHz PVC1 (AM OSC TRIM.) MAXIMUM
3 600KHz 600KHz AM COIL (AM ANT COIL) OUTPUT
4 1400KHz 1400KHz PVC1 (AM ANT TRIM.)
5 REPEAT STEPS 3 AND 4 TO OBTAIN BEST TRACKING.
FM I.F. ALIGNMENT
1. Set the FUNCTION SELECTOR to RADIO & FM BAND.
2. Connect a SWEEPSCOPE OUTPUT to pin5 of IC001 through a 20pF capacitor and ground.
3. Connect a SWEEPSCOPE INPUT to pin16 or 17 of IC001 through a 1uf capacitor and ground.
STEP SET SIGNAL SET DIAL ADJUST ADJUST FOR
1
10.7MHz GANG OPEN T502
CENTER
& MAXIMUM OUTPUT
MAX.AMPLITUDE
BALANCED CURVE
FM R.F. ALIGNMENT
1. Connect an RF generator to the FM antenna terminal and ground.
2. Connect a SCOPE & VTVM across the speaker output.
STEP SET SIGNAL SET DIAL ADJUST ADJUST FOR
1
2 108MHz PVC1 (FM OSC TRIM.) MAXIMUM
3 90MHz 90MHz L504 (FM RF COIL) OUTPUT
4 106MHz 106MHz PVC1 (FM RF TRIM)
5 REPEAT STEPS 3 AND 4 TO OBTAIN MAX ADJUST.
64MHz
L502 (FM OSC COIL)
CD ALIGNMENT
Auto alignment.
4
OFF
TUNER
BLOCK DIAGRAM
CD8227
POWER AMP
POWER SUPPLY
SA2111N
CD
LED
DISPLAY
FM 'RF
AM 'RF
FM/AM IF
CD MP3
KEY BOARD
TC94A58FAG
4.CH.QRIVOR
SA1469PH
ANT
SANYO
CD MECH
DA11B3NF
HEAD AMP
TA2157FN
6
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