AV-N29220
SAFETY PRECAUTIONS
1. The design of this product contains special hardware, many9. Isolation Check
circuits and components specially for safety purposes. For(Safety for Electrical Shock Hazard)
continued protection, no changes should be made to the originalAfter re-assembling the product, always perform an isolation
design unless authorized in writing by the manufacturer.check on the exposed metal parts of the cabinet (antenna
Replacement parts must be identical to those used in the originalterminals, video/audio input and output terminals, Control knobs,
circuits. Qualified personnel should perform Service only.metal cabinet, screw"heads, earphone jack, control shafts, etc.)
to be sure the product is safe to operate without danger of
2. Alterations of the design or circuitry of the products should not beelectrical shock.
made. Any design alterations or additions will void the(1) Dielectric Strength Test
manufacturer's warranty and will further relieve the manufacturerThe isolation between the AC primary circuit and all metal parts
of responsibility for personal injury or property damage resultingexposed to the user, particularly any exposed metal part having a
therefrom.return path to the chassis should withstand a voltage of 3000V
AC (r.m.s.) for a period of one second.
3. Many electrical and mechanical parts in the products have(. . . . Withstand a voltage of 1100V AC (r.m.s.) to an appliance
special safety-related characteristics. These characteristics arerated up to 120V, and 3000V AC (r.m.s.) to an appliance rated
often not evident from visual inspection nor can the protection200V or more, for a period of one second.)
afforded by them necessarily be obtained by using replacementThis method of test requires test equipment not generally found
components rated for higher voltage, wattage, etc. Replacementin the service trade.
parts that have these special safety characteristics are identified(2) Leakage Current Check
in the parts list of Service manual. Electrical componentsPlug the AC line cord directly into the AC outlet (do not use a line
having such features are identified by shading on theisolation transformer during this check.). Using a "Leakage
schematics and by (!!!!) on the parts list in Service manual.Current Tester", measure the leakage current from each exposed
The use of a substitute replacement which does not have themetal part of the cabinet, particularly any exposed metal part
same safety characteristics as the recommended replacementhaving a return path to the chassis, to a known good earth
part shown in the parts list of Service manual may cause shock,ground (water pipe, etc.). Any leakage current must not exceed
fire, or other hazards.0.5mA AC (r.m.s.).
However, in tropical area, this must not exceed 0.2mA AC
4. Don't short between the LIVE side ground and ISOLATED(r.m.s.).
(NEUTRAL) side ground or EARTH side ground when"""" Alternate Check Method
repairing.Plug the AC line cord directly into the AC outlet (do not use a line
Some model's power circuit is partly different in the GND. Theisolation transformer during this check.). Use an AC voltmeter
difference of the GND is shown by the LIVE : (") side GND, thehaving 1000 ohms per volt or more sensitivity in the following
ISOLATED(NEUTRAL) : (#) side GND and EARTH : ($) sidemanner. Connect a 1500! 10W resistor paralleled by a 0.15#F
GND. Don't short between the LIVE side GND andAC-type capacitor between an exposed metal part and a known
ISOLATED(NEUTRAL) side GND or EARTH side GND andgood earth ground (water pipe, etc.). Measure the AC voltage
never measure with a measuring apparatus (oscilloscope etc.)across the resistor with the AC voltmeter. Move the resistor
the LIVE side GND and ISOLATED(NEUTRAL) side GND orconnection to each exposed metal part, particularly any exposed
EARTH side GND at the same time.metal part having a return path to the chassis, and measure the
If above note will not be kept, a fuse or any parts will be broken.AC voltage across the resistor. Now, reverse the plug in the AC
outlet and repeat each measurement. Any voltage measured
5. If any repair has been made to the chassis, it is recommendedmust not exceed 0.75V AC (r.m.s.). This corresponds to 0.5mA
that the B1 setting should be checked or adjusted (SeeAC (r.m.s.).
ADJUSTMENT OF B1 POWER SUPPLY).However, in tropical area, this must not exceed 0.3V AC (r.m.s.).
This corresponds to 0.2mA AC (r.m.s.).
6. The high voltage applied to the picture tube must conform with
that specified in Service manual. Excessive high voltage can
AC VOLTMETER
cause an increase in X-Ray emission, arcing and possible(HAVING 1000 !/V,
component damage, therefore operation under excessive highOR MORE SENSITIVITY)
voltage conditions should be kept to a minimum, or should be
prevented. If severe arcing occurs, remove the AC power
immediately and determine the cause by visual inspection
(incorrect installation, cracked or melted high voltage harness,0.151F AC-TYPE
poor soldering, etc.). To maintain the proper minimum level of
soft X-Ray emission, components in the high voltage circuitryPLACE THIS PROBE
including the picture tube must be the exact replacements orON EACH EXPOSED
alternatives approved by the manufacturer of the complete1500 ! 10WMETAL PART
product.GOOD EARTH GROUND
7. Do not check high voltage by drawing an arc. Use a high voltage
meter or a high voltage probe with a VTVM. Discharge the
picture tube before attempting meter connection, by connecting
a clip lead to the ground frame and connecting the other end of
the lead through a 10k! 2W resistor to the anode button.
8. When service is required, observe the original lead dress. Extra
precaution should be given to assure correct lead dress in the
high voltage circuit area. Where a short circuit has occurred,
those components that indicate evidence of overheating should
be replaced. Always use the manufacturer's replacement
components.
No.518333 |
ACEC
