SAFETY PRECAUTIONS
Operation of the monitor outside of its cabinet or with its back
removed involves ashock hazard. Work on these models should
only be performed by those who are thoroughly familiar with
precautions necessary when working on high voltage equipment.
Exercise care when servicing this chassis with power applied.
Many Bplus and video input terminals are exposed which, if
carelessly contacted, can cause serious shock or result in damage
to the chassis. Maintain interconnecting ground lead connec-
tions between chassis, picture tube dag and power PWB earth
when operating chassis.
Certain HV failures can increase X-ray radiation. The monitor
should not be operated with HV levels exceeding the sp>ecified
rating for their chassis type. The maximum operating HV
specified for the chassis used in these receivers is 12 KV -f 1
—2KV at zero beam current with aline voltage of 220V AC.
Higher voltage may also increase possibility of failure in HV
supply.
It is important to maintain specified values of all components
in the horizontal and high voltage circuits and anywhere else
in the monitor that could cause arise in high voltage or
operating supply voltages. No changes should be made to the
original design of the monitor.
Components shown in the shaded areas on the schematic
diagram and/or identified by an Sin the replacement parts list
should be replaced only with exact Factory reconunended
replacement parts. The use of unauthorized substitute parts may
create ashock, fire. X-radiation, or other hazard.
To determine the presence of high voltage, use an accurate, high
impedance, HV meter connected between second anode lead
and the CRT dag grounding device. When servicing the High
Voltage System, remove static charge by connecting alOK ohm
resistor in series with an insulated wire (such as atest probe)
between picture tube dag and 2nd anode lead. (Before AC line
cord is disconnected from AC supply).
The picture tube used in this monitor employs integralimplo-
sion protection. Replace with tube of the same type numbe)
for continued safety. Do not lift picture tube by the neck. Handle
the picture tube only when wearing shatter-proof goggles and
after discharging the high voltages completely. Keep others
without shatter-proof goggles away.
SAFETY INSPECTION
Before returning the monitor to the user, perform the follow-
ing safety checks;
PROTECT YOUR CUSTOMER
1.
Inspect all wire harmless assemblies to make certain that
the wires are not pinched or that any between hardware is
not lodged between the chassis and other metal parts in the
monitor.
2. Replace all protective devices such as non-metallic control
knobs, insulating fishpapers, cabinet backs, adjustment and
compartment covers or shields, isolation resistor-capacity!
networks, mechanical insulators, etc.
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3. To be sure that no shock hazard exists, acheck for the
presence of leakage current should be made at each exposed
metal part having areturn path to the chassis (input terminal,
cabinet metal, screw heads, knobs and/or shafts, escutcheon, ^
etc.) in the following manner.
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Plug the AC line cord directly into a220V AC receptacle.'
(Do not use an Isolation Transformer during these checks.)
All checks must be repeated with the AC line cord plug con-
nections reversed. (If necessary, anonpolarized adapter plug
must be used only for the purpose of completing these
checks.)
If available, measure current using an accurate leakage current
tester. (Use Standard Equipment Item No. 21641 .)Any reading I
of 0.26 Aor more is excessive and indicates apotential shock
hazard which must be corrected before returning the monitor
to the owner.
If areliable leakage current tester is not available, an alternate
method of measurement should be used. Using two clip leads,
connect a1.5K ohm, 10 watt resistor in parallel with a0.15MF
capacitor in series with aknovsTi earth ground. Use aVTVM
or VOM with 1000 ohms per volts sensitivity, or higher to
measure the AC voltage drop across the resistor. Any reading
of 0.35 volt RMS or more is excessive and indicates apotential
shock hazard which must be corrected before returning the
monitor to the owner.
Fig. 1, Voltmeter Hook-up for Safety Check
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