Trident IS-TVHD30, Руководство по обслуживанию

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Safety precautions
After the original service problem has been corrected, a check should be made of the following:
FIRE & SHOCK HAZARD
1. Be sure that all components are positioned in such a way as to avoid possibility of adjacent
component shorts. This is especially important on those chassis, which are transported to and from
the repair shop.
2. Never release a repair unless all protective devices such as insulators, barriers, covers, shields,
strain reliefs, and other hardware have been reinstalled per original design.
3. Soldering must be inspected to discover possible cold solder joints, frayed leads, damaged
insulation (including A.C. cord), solder splashes or sharp solder points. Be certain to remove all
loose foreign particles.
4. Check for physical evidence of damage or deterioration to parts and components, and replace if
necessary follow original layout, lead length and dress.
5. No leads or components should touch a receiving tube or a resistor rated at 1 watt or more. Lead
tension around protruding metal surfaces must be avoided.
6. All critical components such as fuses, flameproof resistors, capacitors, etc. must be replaced with
exact factory types. Do not use replacement components other than those specified or make
unrecompensed circuit modifications.
7. After re-assembly of the set always perform an A.C. leakage test on all exposed metallic parts of
the cabinet, (the channel selector knob, antenna terminals, handle and screws) to be sure the set is
safe to operate without danger of electrical shock. Do not use a line isolation transformer during
this test. Use an A.C. voltmeter, having 5000 ohms per volt or more sensitivity, in the following
manner: connect a 1500ohm 10watt resistor, paralleled by a 0.15uF. 150V A.C. type capacitor
between a known good earth ground 9water pipe, conduit, etc. and the exposed metallic parts, one
at a time. Measure the A.C. voltage across the combination of 1500ohm resistor and 0.15uF
capacitor. Reverse the A.C. plug and repeat A.C. voltage measurements for each exposed metallic
part. Voltage measured must not exceed 0.75 volts R.M.S. This corresponds to 0.5 milliamp A.C.
Any value exceeding this limit constitutes a potential shock hazard and must be corrected
immediately.
GRAPHIC SYMBOLS:
It is intended to alert the service personnel to the presence of uninsulated dangerous
voltage that may be of sufficiently magnitude to constitute a risk of electric shock.
It is intended to alert the service personnel to the presence of important safety
information in service literature.
X-RADIATION
Too excessive voltage will cause harmful X-ray. To avoid this radiation hazard, the high voltage
should fall within the limitation. The appliance works at AC 120V, 60Hz. The high voltage of zero
Attention:
This service manual is only for service personnel to take reference with. Before
servicing please read the following points carefully.