Belson BSA-1520MP3, Service Manual

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IMPORTANT SERVICE SAFETY INFORMATION
1.SAFETY PRECAUTIONS
2. PRODUCT SAFETY NOTICE
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 dose 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.
3. Servicing precautions
caution: before servicing the unit covered by this service by this service
manual and its supplements. Read and follow the SAFETY PRECAUTIONS on
this page. NOTE: if unforeseen circumstances create a conflict 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
(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 electrical capacitor
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 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.
4. Laser precautions
Warning!!
1. When servicing. (In case it is necessary to confirm laser beam
emission ) be sure not to place your eyes any closer than 1 or
30cm from the surface of the objective lens on the Optical
Pickup block.
HANDLING THE LASER PICKUP
2. Laser Diodes Are Extremely Susceptible To damage from static
electricity even if a static discharge dies not ruin the diode, it can
shorten its life or cause it to work improperly. When replacing the
the pickup, use a conductive mat on the floor and desk and wear
a wrist band connected to ground through a 1 M 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.
Before:
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 bee n
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 to put back in place all protective devices, including , but not limited
to , nonmetallic control knobs, insulating fishpapers,
adjustment and compartment covers/shields and isolating resistor/
capacitor networks. Do not operate this 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.
Leakage current hot check - with the unit completely reassembled ,plug the AC
line cord directly into a 120V AC outlet. (Do not use an iso lation 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.) To all exposed metal parts of the
Unit (antennas, handle bracket, metal cabinet, screw heads , metallic overlays,
control shaft, 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 TAHT MUST BE ELIMINATED RETURNING THE UNIT TO THE CUSTOMER.
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 jumpered AC PLUG AND EACH
Exposed metallic cabinet part on the unit, such as screw heads, 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
(READING SHOULD
NOT BE ABOVE
0.5mA)
LEAKAGE
CURRENT
TESTER
EARTH
GROUND
DEVICE
UNDER
TEST
2-WIRE CORD
ALSO TEST WITH
PLUG REVERSED
(USING AC ADAPTER
PLUG AS REQUIRED)
ANTENNA
TERMINAL
OHMMETER
OM
EXPOSED
METAL
PAR T
!
AC LEAKAGE TEST
2