1. SAFETY INSTRUCTIONS .
GENERAL GUIDELINES exposed metallic part a return path to the
1. It is advised to insert an isolation transformer chassis the reading should be between
in the AC supply before servicing a hot 4Mohm and the 20Mohm. When the exposed
chassis. metal does not have a return path to the
chassis, the reading must be infinite.
2. Potentials as high as 33KV are present when
this receiver is in operation. Operation of the LEAKAGE CURRENT HOT CHECK
receiver without the rear cover involves the 1. Plug the AC cord directly in to the AC outlet.
danger of a shock hazard from the receiver Do not use an isolation transformer for this
power supply. Servicing should not be check.
attempted by any one who is not competent 2. Connect a 2Kohm 10W resistor in series with
with the precautions necessary when working an exposed metallic part on the receiver and
on the high voltage equipment. Always an earth, such as a water pipe.
discharge the anode of the tube. 3. Use an AC voltmeter with high impedance to
measure the potential across the resistor.
3. When servicing observe the original lead 4. Check each exposed metallic part and
dress in the high voltage circuits. If a short check the voltage at the each point.
circuit is found, replace all the parts which 5. Reverse the AC plug at the outlet and repeat
have been overheated or damaged by the each of the above measurements.
short circuit. 6. The potential at the any point should not
exceed 1.4 Vrms. In case a measurement is
4. Always use the manufacturer?s replacement outside the limits specified, there is the
safety components. The critical safety possibility of a shock hazard, and the receiver
components marked with on the should be repaired and rechecked before it
schematics diagrams should not be replaced is returned to the customer.
by other substitutes. Other substitute may
create the electrical shock, fire or other
hazards. Take attention to replace the
spacers with the originals. Furthermore where HOT CHECK CIRCUIT
a short circuit has occurred, replace those AC-Voltmeter
components that indicate evidence of TO INSTRUMENTS
overheating. EXPOSED
METALLIC PARTSWater pipe
(earth)
5. After servicing, see that all the protective
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
Figure 1
long time of period of time, unplug the
power cord from the AC outlet.
X-RAY RADIATION WARNING
The primary source of X-ray radiation in this receiver
7. After servicing make the following leakage
current checks to prevent the customer from is the picture tube. The chassis is specially
constructed to limit X-ray radiation. For continued X-
being exposed to shock hazard.
LEAKAGE CURRENT COLD CHECK ray radiation protection, replace the tube with the
same type of the original one.
1. Unplug the AC cord and connect a jumper
between the two prongs of the plug.
CAUTION
AFTER REMOVAL OF THE ANODE CAP, DISCHARGE THE
2. Turn the receiver?s power switch on.
ANODE OF THE PICTURE TUBE AND THE ANODE CAP TO
THE METAL CHASSIS, CRT SHIELD, OR THE CARBON
3. Measure the resistance value with an PAINTED ON THE CRT WITH A HIGH VOLTAGE PROBE
ohmmeter, between the jumpered AC plug
AND MULTIMETER (SELECT VDC) AND THEN SHORT
and each exposed metallic cabinet part on CIRCUIT DIRECTLY TO DISCHARGE COMPLETELY
the receiver, such as screw heads, aerials,
connectors, control shafts etc. When the
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ACEC
BEKO
