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Service Manual
C7-C8 Chassis
CONTENTS PAGE
Safety Instructions
Technical Specifications
Special Features
Remote Control
Preperations
Operating the TV
IC Datasheets&Specs
Pin Voltages of IC's
Electrical and Service Adjustments
Channel Frequency Tables
Part List
Circuit Diagrams Attached
-2-
1. SAFETY INSTRUCTIONS ^
and each exposed metallic cabinet part on
GENERAL GUIDELINES the receiver, such as screw heads, aerials,
connectors, control shafts etc. When the
1. It is advised to insert an isolation transformer exposed metallic part a return path to the
in the AC supply before servicing a hot chassis the reading should be between
chassis. 4Mohm and the 20Mohm. When the
exposed metal does not have a return path
2. Potentials as high as 33KV are present when to the chassis, the reading must be infinite.
this receiver is in operation. Operation of the
receiver without the rear cover involves the LEAKAGE CURRENT HOT CHECK
danger of a shock hazard from the receiver
power supply. Servicing should not be 1. Plug the AC cord directly in to the AC
attempted by any one who is not outlet. Do not use an isolation transformer
competent with the precautions necessary for this check.
when working on the high voltage 2. Connect a 2Kohm 10W resistor in series with
equipment. Always discharge the anode of an exposed metallic part on the receiver
the tube. and an earth, such as a water pipe.
3. Use an AC voltmeter with high impedance
3. When servicing observe the original lead to measure the potential across the resistor.
dress in the high voltage circuits. If a short 4. Check each exposed metallic part and
circuit is found, replace all the parts which check the voltage at the each point.
have been overheated or damaged by the 5. Reverse the AC plug at the outlet and
short circuit. repeat each of the above measurements.
6. The potential at the any point should not
4. Always use the manufacturer's replacement exceed 1.4 Vrms. In case a measurement is
safety components. The critical safety outside the limits specified, there is the
components marked with on the possibility of a shock hazard, and the
schematics diagrams should not be receiver should be repaired and rechecked
replaced by other substitutes. Other before it is returned to the customer.
substitute may create the electrical shock,
fire or other hazards. Take attention to
replace the spacers with the originals.
Furthermore where a short circuit has HOT CHECK CIRCUIT
occurred, replace those components that AC-Voltmeter
indicate evidence of overheating. TO INSTRUMENTS
EXPOSED
5. After servicing, see that all the protective METALLIC PARTS Water pipe
(earth)
devices such as insulation barriers, insulation
papers, shields and isolation R-C
combinations are correctly installed. 2 K Ohm
6. When the receiver is not being used for a
long time of period of time, unplug the
Figure 1
power cord from the AC outlet.
X-RAY RADIATION WARNING
7. After servicing make the following leakage
The primary source of X-ray radiation in this receiver
current checks to prevent the customer
is the picture tube. The chassis is specially
from being exposed to shock hazard.
constructed to limit X-ray radiation. For continued X-
ray radiation protection, replace the tube with the
LEAKAGE CURRENT COLD CHECK
same type of the original one.
CAUTION
1. Unplug the AC cord and connect a jumper
AFTER REMOVAL OF THE ANODE CAP, DISCHARGE
between the two prongs of the plug.
THE ANODE OF THE PICTURE TUBE AND THE ANODE
CAP TO THE METAL CHASSIS, CRT SHIELD, OR THE
2. Turn the receiver's power switch on.
CARBON PAINTED ON THE CRT WITH A HIGH
VOLTAGE PROBE AND MULTIMETER (SELECT VDC)
3. Measure the resistance value with an
AND THEN SHORT CIRCUIT DIRECTLY TO DISCHARGE
ohmmeter, between the jumpered AC plug
COMPLETELY.
-3-
Television
Thank you for buying this television which is designed to give you many years of
satisfactory service.
You may already be familiar with using a television but do please take time to read these
instructions. They are designed to familiarise you with the unit's many new features
and to ensure you get the very best out of your purchase.
Special features