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IMPORTANT SERVICE SAFETY PRECAUTION
Service work should be performed only by qualified service technicians who are thoroughly familiar with all
of the following safety checks and servicing guidelines.
WARNING
1.
For continued safety, do not attempt to modify
the circuit.
2.
Disconnect the AC power before servicing.
3.
Semiconductor heat sinks are potential shock
hazards when the chassis is operating.
SERVICING THE HIGH VOLTAGE SYSTEM AND
PICTURE TUBE
When servicing the· high voltage system, remove the
static charge by connecting a 20kohm resistor in
series with an insulated wire( such as a test probe)
between the chassis and the anode lead. (The AC
line cord should be disconnected from the AC out-
let.)
1 .
The picture tube in this display monitor employs
integral implosion protection.
2.
Replace with a tube of the same type and num-
ber for continued safety.
3.
Do not lift the picture tube by the neck.
4.
Handle the picture tube only when wearing shat-
ter proof goggles and after discharging the high
voltage anode completely.
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 a current
solid state display monitor is the tube. How-
ever ,the picture tube does not emit measurable
X-ray radiation if the high voltage is as specified
in the "high voltage check" instruction.
3
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 serviceman have available at
all times an accurate high voltage meter. The
calibration of this meter should be checked pe-
riodically.
3.
High voltage should always be kept at the rated
value - no higher. Operation at high voltages may
cause a failure of the picture tube or high voltage
circuitry and,also under certain conditions,may
produce radiation in excess of desirable levels.
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,the bright-
ness should
4
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 troubleshooting and taking test measure-
ments on a display monitor with excessively high
voltage, avoid being unnecessarily close to the
display monitor. Do not operate the display
monitor longer than is necessary to locate the
cause of excessive voltage.
BEFORE RETURNING THE DISPLAY MONITOR
Fire and Shock Hazard
Before returning the display monitor to the user,per-
form the following safety checks:
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