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SAFETY PRECAUTIONS
DO NOT OPERATE THIS INSTRUMENT OR PERMIT IT TO BE OPER- Do not remove, install, or otherwise handle the picture tube in any manner with-
ATED WITHOUT ALL PROTECTIVE DEVICES INSTALLED AND out first putting on shatterproof goggles equipped with side shields. People not so
FUNCTIONING. SERVICERS WHO DEFEAT SAFETY FEATURES OR equipped must be kept safely away while picture tubes are handled. Keep the
FAIL TO PERFORM SAFETY CHECKS MAY BE LIABLE FOR ANY picture tube away from your body. Do not handle the picture tube by its neck.
RESULTING DAMAGE, AND MAY EXPOSE THEMSELVES AND OTH- Some "in-line" picture tubes are equipped with a permanently attached deflection
ERS TO POSSIBLE INJURY. yoke; because of potential hazard, do not try to remove such "permanently at-
READ AND COMPLY WITH ALL CAUTION AND SAFETY-RELATED tached" yokes from the picture tube.
NOTES ON OR INSIDE THE RECEIVER CABINET, AND THE RE- X-RADIATION AND HIGH VOLTAGE LIMITS - Because the picture
CEIVER CHASSIS, OR ON THE PICTURE TUBE. tube is the primary source of X-radiation in solid-state TV receivers, it is specially
SAFETY GLASSES SHOULD BE USED WHEN SERVICING ELEC- constructed to prohibit X-radiation emissions. For continued X-radiation protec-
TRONIC INSTRUMENTS. INADVERTENTLY OVERSTRESSING COM- tion, a replacement picture tube must be the same type as the original. The picture
PONENTS MAY CAUSE THEM TO SHATTER, DISCHARGING SMALL shields, mounting hardware and lenses (projection TV) may also perform an X-
PARTICLES. radiation protection function, and they must be correctly in place. Anode connec-
tors contain an X-radiation shield - use only the manufacturer's specified anode
DESIGN ALTERATION WARNING - Do not alter or add to the mechanical or connectors. High voltage must be measured each time servicing that involves
electrical design of this instrument. Design alterations and additions may alter the power supply, horizontal deflection or high voltage circuits is performed. Correct
safety characteristics of this instrument and create a hazard to the user. Design operation of the X-radiation circuits must also be confirmed each time these cir-
alterations or additions may void the manufacturer's warranty and may make you, cuits are serviced (X-radiation circuits may also be called "horizontal disable" or
the servicer, responsible for personal injury or property damage resulting there- "hold-down" circuits). Read and apply high voltage limits and, if the chassis is so
from. equipped, the X-radiation protection circuit specifications. These limits and speci-
BEFORE RETURNING AN INSTRUMENT TO THE CUSTOMER, always fications are given on instrument labels and are included in this service data. High
make a safety check of the entire instrument, including, but not limited to, the voltage is maintained within specified limits by close-tolerance safety-related com-
following items: ponents (and adjustments) in the high voltage circuit. If high voltage exceeds
FIRE AND SHOCK HAZARD specified limits, check each safety related component specified on the schematic
and take corrective action.
1. Never release a repaired unit unless all protective devices such as insula-
tors, barriers, covers, strain reliefs and other protective hardware have been ANTENNA LEAKAGE RESISTANCE CHECK - With the instrument AC
installed in accordance with the original design. plug removed from the AC source, connect an electrical jumper across the two AC
plug prongs. Place the instrument AC switch (if applicable) in the "on" position.
2. Be sure that there are no cabinet openings through which an adult or a child Connect one lead of an ohmmeter to the AC plug prongs and touch the other
might be able to insert their fingers and contact a hazardous voltage. Such ohmmeter lead, in turn, to each (exposed) antenna input terminal screw and/or
openings include, but are not limited to: (a) spacing between picture tube coaxial connector. If the measured resistance is less than 1.0 Megohm, or greater
and cabinet mask, (b) excessively wide cabinet ventilation slots, and (c) an than 5.2 Megohm, an abnormality exists which must be corrected before the in-
improperly fitted or incorrectly secured back cover or cabinet. strument is returned to the customer. Repeat this test with the AC switch in the
3. Observe original lead dress. Take care to restore leads to their original "off" position.
dress. Make sure that leads are not in contact with sharp edges or thermally
hot parts. Always inspect in all areas for pinched, out-of-place or frayed
wiring. Do not change spacing between adjacent components, or between reading
components and printed circuit board. Check the AC power cord for dam- should be
age. < 0.5mA
DEVICE LEAKAGE
probe all
4. Be certain to remove loose solder balls and all other loose foreign particles. UNDER CURRENT
exposed
5. Check components, parts and/or wiring for physical evidence of damage, TEST TESTER
metal
overheating or deterioration, and replace if necessary. Determine the cause surfaces + -
of damage and/or overheating and, if necessary, take corrective action to
remove any potential safety hazard.
6. Parts Replacement - Many instruments electrical and mechanical parts have
2-wire
special safety-related characteristics, some of which are often not evident
cord
from visual inspection, and the protection they give cannot necessarily be also test with
obtained by replacing them with components rated for higher voltage, watt- plug reversed
age, etc. Parts that have special safety characteristics are identified in this (use ac adapter earth
service data by a ( ) on schematics and in the parts list. Use of a substitute plug as required) ground
replacement that does not have the same safety characteristics as the recom-
mended replacement part in the service data parts list may create shock, fire LEAKAGE CURRENT HOT CHECK FOR 2-WIRE OR 3-WIRE
and/or other hazards. Always consult the appropriate current service litera- GROUNDED CORD SETS - With the instrument completely reassembled,
ture for the latest information. plug the AC line cord into the mains AC outlet at normal line voltage via a non-
7. Some instruments chassis' normally have 85VAC (RMS) between chassis polarized adapter. DO NOT GROUND THE 3RD PRONG OF THE ADAPTER
and earth ground, regardless of the AC plug polarity. Some instrument AND DO NOT USE AN ISOLATION TRANSFORMER. Use a leakage current
chassis' are electrically connected directly to one conductor of the AC power tester or metering system that complies with American National Standards Insti-
cord. Some instrument chassis' have a secondary ground system in addition tute (ANSI) C101.1 Leakage Current for Appliances and with Underwriters Labo-
to the main chassis ground. This secondary ground system is not isolated ratories (UL) 1492 (Section 67). With the instrument AC switch first in the "on"
from the AC power line. The two ground systems are electrically separated position and then in the "off" position, measure from a known earth ground (metal
by insulating material that must not be defeated or altered. Thus, when water pipe, conduit, etc.) to all exposed metal parts of the instrument (antennas,
servicing any unit always use a separate isolation transformer for the chas- handle bracket, metal cabinet, screwheads, metallic overlays, control shafts, etc.).
sis. Failure to use a separate isolation transformer may expose the servicer Any current measured must not exceed 0.5 milliampere. Reverse the adapter plug
to possible shock hazard, and may cause damage to servicing instruments. in the outlet and repeat the test. ANY MEASUREMENTS NOT WITHIN THE
8. Many electronic products use a polarized AC line cord (one wide pin on the LIMITS SPECIFIED HEREIN INDICATE A POTENTIAL SHOCK HAZ-
plug). Defeating this safety feature may create a potential hazard to the ARD THAT MUST BE ELIMINATED BEFORE RETURNING THE IN-
servicer and the user. Extension cords that do not incorporate the polarizing STRUMENT TO THE CUSTOMER OR BEFORE CONNECTING THE
feature should never be used. ANTENNA OR ACCESSORIES. If a leakage current tester is not available,
connect a 1.5 Kohm, 10 Watt resistor, in parallel with a 0.15