SERVICE MANUAL
3Y18 CHASSIS
Design and specifications are subject to change without prior notice.
( ONLY REFERRENCE)
ENGINEER BY: CHECKED BY: PPROVED BY:
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Contents
Safety Notice
Technical specification-------------------------------------------Chassis Block Diagram--------------------------------------------9
IC Block Diagram -------------------------------------------------10-15
Transistor mark ----------------------------------------------------16
PCB Top/Bottom layer -------------------------------------------17-19
Service Adjustments ------------------------------------------- 20-24
Purity and Convergence Adjustment ----------------------------25
Control Location ---------------------------------------------------26
Input and Output Terminals----------------------------------------27
Operation Instructions
Mechanical Disassemblies----------------------------------------36
Circuit Diagram-----------------------------------------------------37
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3-8
------------------------------------------28-35
Safety Notice
SAFETY PRECAUTIONS
1:An isolation transformer should be connected in the power line between the receiver and
the AC line when a service is performed on the primary of the converter transformer of the
set.
2:Comply with all caution and safety-related notes provided on the cabinet back, inside the
cabinet, on the chassis or the picture tube.
3:When replacing a chassis in the cabinet, always be certain that all the protective devices
are installed properly,such as,control knobs, adjustment covers or shields, barriers,isola tion resistor-capacitor networks etc.. Before returning any television to the customer,the
service technician must be sure that it is completely safe to operate without danger of
electrical shock.
X-RADIATION PRECAUTION
The primary source of X-RADIATION in television receiver is the picture tube. The picture
tube is specially constructed to limit X-RADIATION emissions. For continued X-RADIATION
protection, the replacement tube must be the same type as the original including suffix
letter. Excessive high voltage may produce potentially hazardous X-RADIATION. To avoid
such hazards, the high voltage must be maintained within specified limit. Refer to this
service manual, high voltage adjustment for specific high voltage limit. If high voltage exceeds specfied limits, take necessary corrective action. Carefully follow the instructions for
+B1 volt power supply adjustment, and high voltage check to maintain the high voltage
within the specified limits.
PRODUCT SAFETY NOTICE
Product safety should be considered when a component replacement is made in any area
of a receiver. Components indicated by mark in the parts list and the schematic diagram
designate components in which safety can be of special significance. It is particularly
recommended that only parts designated on the parts list in this manual be used for component replacement designated by mark . No deviations fromresistance wattage or voltage ratings may be made for replacement items designated by mark .
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IC 201 (LA7693*)
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IC500 (CQ0765)
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