Sharp 20J-20MJ10 Руководство по эксплуатации - Страница 2
Просмотреть онлайн или скачать pdf Руководство по эксплуатации для ТЕЛЕВИЗОР Sharp 20J-20MJ10. Sharp 20J-20MJ10 29 страниц. Chassis no. sn-70
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19J-M100/100S/150/20J-M100
CJ19M10/CJ20M10/ 20MJ10
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:
WARNING
1. For continued safety, no modification of any circuit
should be attempted.
2. Disconnect AC power before servicing.
3. Semiconductor heat sinks are potential shock
hazards when the chassis is operating.
4. The chassis in this receiver has two ground systems
which are separated by insulation material. The non-
isolated (hot) ground system is for the B+ voltage
regulator circuit and the horizontal output circuit.The
isolated ground system is for the low B+ DC voltages
and the secondary circuit of the high voltage
transformer.
To prevent electrical shock use an isolation
transformer between the line cord and power
receptacle, when servicing this chassis.
4A 125V
SERVICING OF HIGH VOLTAGE SYSTEM
AND PICTURE TUBE
When servicing the high voltage system, re-
move the static charge by connecting a 10k
ohm resistor in series with an insulated wire
(such as a test probe) between the picture tube
ground and the anode lead. (AC line cord
should be disconnected from AC outlet.)
1. Picture tube in this receiver employs integral
implosion protection.
2. Replace with tube of the same type number for
continued safety.
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.
CAUTION: FOR CONTINUED
PROTECTION AGAINST A
RISKOF FIRE, REPLACE
ONLY WITH SAME TYPE 4A-
125V FUSE.
X-RADIATION AND HIGH VOLTAGE
LIMITS
1. Be sure all service personnel are aware of the
procedures and instructions covering X-radiation. The
only potential source of X-ray in current solid state
TV receivers is the picture tube. However, the picture
tube does not emit measurable X-Ray radiation if the
high
voltage is as specified in the "High Voltage Check"
instructions.
It is only when high voltage is excessive that X-
radiation is capable of penetrating the shell of the
picture tube including the lead in glass material. The
important precaution is to keep the high voltage below
the maximum level specified.
2. It is essential that service personal have available at
all times an accurate high voltage meter.
The calibration of this meter should be checked
periodically.
3. High voltage should always be kept at the rated value
no higher. Operation at higher voltages may cause
a failure of the picture tube or high voltage circuitry
and; also under certain conditions, may produce
radiation that exceeds specifications.
4. When the high voltage regulator is operating properly
there is no possibility of an X-radiation problem. Every
time a color chassis is serviced,
should be tested while monitoring the high voltage
with a meter to be certain that the high voltage does
not exceed the specified value and that it is regulating
correctly.
5. Do not use a picture tube other than that specified or
make unrecommended circuit modifications to the
high voltage circuitry.
6. When trouble shooting and taking test measurements
on a receiver with excessive high voltage, avoid being
unnecessarily close to the receiver.
Do not operate the receiver longer than is necessary
to locate the cause of excessive voltage.
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the brightness