Sylvania 6842THG, Service Manual

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1-2-2 L0604IMP
b. Some monitor chassis normally have 85V
AC(RMS) between chassis and earth ground re-
gardless of the AC plug polarity. This chassis can
be safety-serviced only with an isolation transform-
er inserted in the power line between the receiver
and the AC power source, for both personnel and
test equipment protection.
c. Some monitor 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 insulation material that
must not be defeated or altered.
5. Observe original lead dress. Take extra care to as-
sure 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 ther-
mally hot parts,c. the AC supply,d. high voltage,
and,e. antenna wiring. Always inspect in all areas
for pinched, out of place, or frayed wiring. Check
AC power cord for damage.
6. Components, parts, and/or wiring that appear to
have overheated or are otherwise damaged
should be replaced with components, parts, or wir-
ing that meet original specifications. Additionally,
determine the cause of overheating and/or dam-
age and, if necessary, take corrective action to re-
move any potential safety hazard.
7 Product Safety Notice - Some electrical and me-
chanical parts have special safety-related charac-
teristics which are often not evident from visual
inspection, nor can the protection they give neces-
sarily be obtained by replacing them with compo-
nents rated for higher voltage, wattage, etc.. Parts
that have special safety characteristics are identi-
fied by a (
#
) on schematics and in parts lists. Use
of a substitute replacement that does not have the
same safety characteristics as the recommended
replacement part might create shock, fire, and/or
other hazards. The product's safety is under re-
view continuously and new instructions are issued
whenever appropriate. Prior to shipment from the
factory, our products are strictly inspected to con-
firm they comply with the recognized product safe-
ty and electrical codes of the countries in which
they are to be sold. However, in order to maintain
such compliance, it is equally important to imple-
ment the following precautions when a set is being
serviced.
General Caution of Plasma Display
1. Since the Panel module and front filter are made of
glass, sufficient care shall be taken when handling
the broken module and filter in order to avoid inju-
ry.
2. If necessary to replace Panel module, this work
must be started after the panel module and the
AC/DC Power supply becomes sufficiently cool.
3. Special care must be taken with the display area to
avoid damaging its surface.
4. The Panel Module shall not be touched with bare
hands to protect its surface from stains.
5. It is recommended to use clean soft gloves during
the replacing work of the Panel module in order to
protect, not only the display area of the panel mod-
ule but also the serviceman.
6. The Chip Tube of the panel module (located upper
left of the back of the panel module) and flexible
cables connecting Panel glasses to the drive cir-
cuitry Printed Wiring Boards (P.W.B.) are very
weak, so sufficient care must be taken to prevent
breaking or cutting any of these. If the Chip Tube
breaks the panel module will never work, replace-
ment for a new plasma panel module will be need-
ed.
7. Signal, power supply P.W.B.’s and PDP driving cir-
cuits P.W.B.’s are assembled on the rear side of
the PDP module, take special care with this fragile
circuitry; particularly, Flexible Printed Circuits
bonded to surrounding edges of the glass panel.
They are not strong enough to withstand harsh
outer mechanical forces. Avoid touching the flexi-
ble printed circuits by not only your hands, but also
tools, chassis, or any other object. Extreme bend-
ing of the connectors must be avoided too. In case
the flexible printed circuits are damaged, the cor-
responding addressed portions of the screen will
not be lit and exchange of a glass panel will be re-
quired.