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1.  It is advisable to insert an isolation transformer in the AC supply before servicing this hot chassis.

2.  When servicing, observe the original lead dress, especially the lead dress in the high voltage 

circuits. If a short circuit is found, replace all parts which have been overheated or damaged by 
the short circuit.

3.  After servicing, see to it that all the protective devices such as insulation barriers, insulation 

papers, shields and isolation R-C combinations, are properly installed.

4.  When the receiver is not to be used for a long period of time, unplug the power cord from the AC 

cord outlet.

5.  Potential, as high as 

27.5kV

 is present when this receiver is in operation. Operation of the receiver 

without the rear cover involves the danger of a shock hazard from the receiver power supply. 
Servicing should not be attempted byanyone who is not thoroughly familiar with the precautions 
necessary when working on high voltage equipment. Always discharge the anode of the picture 
tube to the receiver chassis before handling the tube. After servicing make the following 
leakagecurrent checks to prevent the customer from being exposed to shock hazards.

 

 

1.  Unplug the AC cord and connect a jumper between the two prongs on the plug.

2.  Turn on the receiver’s power switch. 

Measure the resistance value, with an ohmmeter, between the jumper AC plug and each exposed 
metallic cabinet part on the receiver, such as screw heads, aerials, connectors, control shafts, 
etc.When the exposed metallic part has a return path to the chassis, the reading should be between 
4 M

Ω

 and 20 M

Ω

. When the exposed metal does not have a return path to the chassis, the reading 

must be infinite.

 

 

1.  Plug the AC cord directly into the AC outlet. Do not use an isolation transformer for this check.

2.  Check a 2 k

Ω

 non-inductive resistor and an AC/DC current meter, in series with each exposed 

metallic part on the receiver in turn and an earth such as a water pipe.

The current from any point should not exceed 0.7 mA peak AC or 2 mA DC. In the case of a 
measurement being outside of these limits specified, there is a possibility of a shock hazard and 
the receiver should be repaired and rechecked before it is returnedto the customer.

Fig. 1

 

,

 

 

Warning:

 

The potential sources of X-Radiation in TV set are the EHT section and the picture tube. When using a 
picture tube test jig for service, ensure that jig is capable of handling 

29.0kV

 without causing X-

Radiation. 

Note:

 It is important to use an accurate periodically calibrated high voltage meter.

1.  Set the brightness to minimum.

2.  Use the remocon to get into Service Mode.

3.  Measure the EHT. The meter reading should indicate 

27.5±1.5kV

 . If the meter indication is out 

of tolerance, immediate service and correction is required to prevent the possibility of premature 
component failure.

4.  To prevent the possibility X-Radiation, it is essential to use the specified picture tube, if service 

replacement becomes necessary.