2. Read and comply with all caution and safety-related Components, parts, and/or wiring that appear to havt
notes on or inside the receiver cabinet, on the receiver overheated or are otherwise damaged should be
chassis, or on the picture tube. replaced with components, parts, or wiring that meei
original specifications. Additionally, determine the
cause of overheating and/or damage and, if
3. Design Alteration Warning - Do not alter or add to necessary, take corrective action to remove any
the mechanical or electrical design of this TV receiver. potential safety hazard.
Design alterations and additions including but not
limited to circuit modifications and the addition of PRODUCT SAFETY NOTICE - Many TV electrical
items such as auxiliary audio and/or video output and mechanical parts have special safety-related
connectors, might alter the safety characteristics of characteristics some of which are often not evident
this receiver and create a hazard to the user. Any from visual inspection, nor can the protection they
design alterations or additions may void the give necessarily be obtained by replacing them with
manufacturer?s warranty and may make you, the components rated for higher voltage, wattage, etc.
servicer, responsible for personal injury or property Parts that have special safety characteristics are
damage resulting therefrom.
identified in Hitachi service data by shading on
schematics and by a A in the parts list. Use of
substitute replacement that does not have the same
4. Picture Tube Implosion Protection Warning - The safety characteristics as the recommended replace-
picture tube in this receiver employs integral implosion ment part in Hitachi service data parts list might
protection. For continued implosion protection, create shock, fire, and/or other hazards. Product
replace the picture tube only with one of the same
type number. Do not remove, install, or otherwise safety is under review continuously and new
handle the picture tube in any manner without first instructions are issued whenever appropriate. For the
putting on shatterproof goggles equipped with side latest information, always consult the appropriate
shields. People not so equipped must be kept safely current Hitachi service literature. A subscription to, or
away while picture tubes are handled. Keep the additional copies of service literature may be obtained
picture tube away from your body. Do not handle the at a nominal charge from Hitachi.
picture tube by its neck.
5. Hot Chassis Warning - a. Some TV receiver chassis
are electrically connected directly to one conductor of
the AC power cord and may be safely serviced without
an isolation transformer only if the AC power plug is
inserted so that the chassis is connected to the
ground side of the AC power source. Confirm that the
AC power plug is inserted correctly with an AC
voltmeter by measuring between the chassis and a
known earth ground. If a voltage reading in excess of
l.OV is obtained, remove and reinsert the AC power
plug in the opposite polarity and again measure the
voltage potential between the chassis and a known
earth ground. b. Some TV receiver chassis normally
have 85V AC (RMS) between chassis and earth
ground regardless of the AC plug polarity. These
chassis can be safely serviced only with an isolation
transformer inserted in the power line between the
receiver and the AC power source, for both personnel
and test equipment protection. c. Some TV receiver
chassis have a secondary ground system in addition
to the main chassis ground. This secondary ground
system is not isolated from the AC power line. The two
ground systems are electrically separated by
insulating material that must not be defeated or
altered.
6. Observe original lead dress. Take extra care to assure
correct lead dress in the following areas: a. near sharp
edges, b. near thermally hot parts - be sure that leads
and components do not touch thermally hot parts, c.
the AC supply, d. high voltage and e. antenna wiring.
Always inspect in all areas for pinched, out-of-plate, or
frayed wiring. Do not change spacing between
components and the printed circuit board. Check AC
power cord for damage.
4 |
ACEC
