This is the 38 pages manual for Akai AJC 2500 Service Manual.
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CAUTION: Before servicing the chassis, read the
section on page 2 of this manual.
"important Service safety Information"
PORTABLE MW/FM/LW RADIO WITH CASSETTE RECORDER
AMIFM TUNER SECTION AM: FERRITE BAR
INTERMEDIATE FREQUENCY AM: 465KH2 +I-1KH2
FM: 10.7MHz +0.1MHz
ANTENNA SYSTEM FM: TELESCOPIC
TUNING RANGE AM: 515~1650I
SPEAKER IMPEDANCE 8 ohm
POWER INPUT AC 230V,50Hz DC 12V
DIMENSIONS 497(W) X 234(H) X 287 (D)mm
IMPORTANT SERVICE SAFETY INFORMATION- 2
DISASSEMBLY INSTRUCTIONS ————————— 3
ALIGNMENT PROCEDURES ————————— 4~5
ADJUSTMENT LOCATIONS ---------- 6
Ic BLOCK DIAGRAM ————————————— 7-12
BLOCK DIAGRAM ———————————————— 13
WIRING DIAGRAM _______________ 14
PRINTED CIRCUIT BOARDS -------- 1524
SCHEMATIC DIAGRAMS —————————— 25-29
EXPLODED VIEW ——————————————— so
EXPLODED VIEW PARTS LIST ————————— 31
REPLACEMENT PARTS LIST ————————— 32-38
INTERMEDIATE FREQUENCY AM: 465KH2 +I-1KH2
FM: 10.7MHz +0.1MHz
IMPORTANT SERVICE SAFETY INFORMATION
Before returning a unit to the customer. always make a safety check of
the entire unit. including. but not limited to the tollowing items:
. 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. he 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
. 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 titted and/or incorrectly
secured cabinet back cover.
. Leakage CLIrrent Hot Check . With the unit completely reassembled,
plug the A 'Iine cord directly into a 120V AC outlet. (Do not use an
isolation tra stormer during this test.) Use a leakage current tester or a
metering system that complies with American National Standards
institute (ANSI) 0101.1"Leakage current for Appliances." and
Underwriters laboratories (UL) 14104507). 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 mitliamp. 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 sHoUl 0
nor as Aaove
AC Leakage Test
TI-.S I“ N l
ALSO TEST WlTl-l
-—--- --—- EARTH
PLUG nevenssu (( GROUND
(USING AC ADAPTER
PLUG AS REQUIRED)
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 ohrnmeler between the jumpered AC
ping and earth exposed metallic cabinet part on the unit. such as
suewheads. antenna. control shafts. handle brackets etc. When the
exposed metallic part has a return path to the chassis. the reading
siioiiirll between i and ‘3 2 megohms When there is no return path to
the chassis the reading must he niiinite it it I'-'r not wrthm the limits
5t ".lItPiI men- l':| the pulsatiulilv at a shock ham”) an” the iimi must he
:u ll'F‘EI .‘ilnl rechecked below It is returned lri llir: customer
TERMINAL —‘——~T .
.0 I ll
2. PRODUCT SAFETY NOTICE
Some electrical and mechanical parts have special safety relat-
characteristics which are ohen not evident from visual inspection. r
can the protection they give necessarily be obtained by replacing the
with components rated for higher voltage. wattage. etc.,F'arts th
have special satety characteristics are identified by a A r
schematic and parts list. Use of a substitute replacement that doles n
have the same safety characteristics as the recommends
replacement part might create shock, fire. and/or other hazard
Product safety is under review continuously and new instructions a
issued whenever appropriate.
3. SERVICING PRECAUTIONS
CAUTION"Botore servicing the unit covered by this seNlce manu
and its supplements read and follow the SAFETY PRECAUTIONS c
this page. NOTE"lf unforeseen circumstances create a conflit
between the following servicing precautions and any of the sale
precautions. always follow the safety precautions. Remember: Sale'
General Servicing Precautions.
a. Always unplug the unit‘s AC power cord from the AC power
(1) removing or reinstalling any component. circuit board. module. or
any other unit assembly.
(2) disconnecting or reconnecting any unit electrical plug or other
(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
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
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 instruments ground lead last.
4. LASER PRECAUTIONS
1. When servicing. (in case it is necessary to conﬁrm Laser Beam
Emission) be sure not to place your eyes any closer than 1 ft or
30cm (tom the surface of the Detective Lens on the Opticval
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
3. There are no adjustable parts in the pickup assembly. If it is
defective. replace the whole pickup assembly.
USE OF CONTROLS. ADJUSTMENTS OR PERFORMANCE
OF PROCEDURES HEREIN MAY RESULT IN HAZARDOUS
lF INTERLOCK FAILS OR IS DEFEATED It-tF LASER LIth'I
IS ABLE It) FUNCTION Illir.‘ LASER If; INVISIBLE. AVOID
DIRECI EXPOSURE TC) BEAM