14VT-N10T(S)
IMPORTANT SERVICE SAFETY PRECAUTION
�Service work should be performed only by qualified service technicians who are
thoroughly familiar with all safety checks and servicing guidelines which follow:
WARNINGX-RADIATION AND HIGH VOLTAGE LIMITS
1. For continued safety, no modification of any circuit1. Be sure all service personnel are aware of the
should be attempted.procedures and instructions covering X-radiation.
2. Disconnect AC power before servicing.The only potential source of X-ray in current solid
3. Semiconductor heat sinks are potential shockstate TV receivers is the picture tube. However, the
hazards when the chassis is operating.picture tube does not emit measurable X-Ray
4. The chassis in this receiver has two ground systemsradiation if the high voltage is as specified in the "High
which are separated by insulation material. The non-Voltage Check" instructions.
isolated (hot) ground system is for the B+ voltageIt is only when high voltage is excessive that X-
regulator circuit and the horizontal output circuit.Theradiation is capable of penetrating the shell of the
isolated ground system is for the low B+ DC voltagespicture tube including the lead in glass material. The
and the secondary circuit of the high voltageimportant precaution is to keep the high voltage
transformer.below the maximum level specified.
To prevent electrical shock use an isolation2. It is essential that servicepersonel have available at
transformer between the line cord and powerall times an accurate high voltage meter.
receptacle, when servicing this chassis.The calibration of this meter should be checked
periodically.
CAUTION : FOR CONTINUED3. High voltage should always be kept at the rated value
PROTECTION AGAINST A-no higher. Operation at higher voltages may cause
RISKOF FIRE, REPLACEa failure of the picture tube or high voltage circuitry
ONLY WITH SAME TYPE 4A-4A 125Vand;also, under certain conditions, may produce
125V FUSE.radiation that exceeds specifications.
4. When the high voltage regulator is operating properly
SERVICING OF HIGH VOLTAGE SYSTEMthere is no possibility of an X-radiation problem.
AND PICTURE TUBEEvery time a color chassis is serviced, the
brightness should be tested while monitoring the
When servicing the high voltage system,
high voltage with a meter to be certain that the high
remove the static charge by connecting avoltage does not exceed the specified value and that
10k ohm resistor in series with an insulatedit is regulating correctly.
wire (such as a test probe) between the pic-5. Do not use a picture tube other than that specified
ture tube ground and the anode lead. (ACor make unrecommended circuit modifications to the
high voltage circuitry.
line cord should be disconnected from AC
6. When trouble shooting and taking test
outlet.)measurements on a receiver with excessive high
1. Note that the picture tube in this receiver employsvoltage, avoid being unnecessarily close to the
receiver.
integral implosion protection.
2. Replace with tube of the same type number forDo not operate the receiver longer than is necessary
continued safety.to locate the cause of excessive voltage.
3. Do not lift picture tube by the neck.
4. Handle the picture tube only when wearing
shatterproof goggles and after discharging the high
voltage anode completely.
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ACEC
SHARP
