SAFETY INSTRUCTION
CAUTION : Do not attempt to modify this product in any way. Unau-GRAPHIC SYMBOLS :
thorized modifications will not only void the warranty, but may lead to
your being liable for any resulting property damage or user injury.The lightning flash with arrowhead symbol,
Service work should be performed only after you are thoroughlywithin an equilateral triangle, is intended to alert
familiar with all of the following safety checks and servicing guide-the service personnel to the presence of uninsu-
lines. To do otherwise, increases the risk of potential hazards andlated ?dangerous voltage? that may be of suffi-
injury to the user.cienty magnitude to constitute a risk of electric
shock.
SAFETY CHECKS
The exclamation point within an equilateral tri-
After the original service problem has been corrected, a check shouldangle is intended to alert the service personnel
be made of the following:to the presence of important safety information
in service literature.
SUBJECT : FIRE & SHOCK HAZARD
Fuse symbol is printed on pcb adjacent to the
1. Be sure that all components are positioned in such a way as tofuse, with ?RISK OF FIRE REPLACE FUSE AS
avoid possibility of adjacent component shorts. This is especiallyMARKED?. The symbol is explained in the ser-
important on those chassis which are transported to and from thevice manual with the following wording or equiv-
repair shop.alent.
2. Never release a repair unless all protective devices such as insula-
tors, barriers, covers, shields, strain reliefs, and other hardware?CAUTION : FOR CONTINUED PROTECTION AGAINST FIRE
have been reinstalled per original design.HAZARD, REPLACE ONLY WITH SAME TYPE (6.3A, 250V)? and
3. Soldering must be inspected to discover possible cold solder joints,?ATTENTION: AFIN D?ASSU UNE PROTECTION PERMANENTE
frayed leads, damaged insulation (including A.C. cord), solderCONTRE LES RISQUES D?INCENDIE, REMPLACER UNIQUE-
splashes or sharp solder points. Be certain to remove all loose for-MENT PAR UN FUSIBLE DE MEME TYPE ET DE ?6.3A, 250V?.
eign particals.
4. Check for physical evidence of damage or deterioration to partsSUBJECT : X-RADIATION
and components, and replace if necessary follow original layout,
lead length and dress.1. Be sure procedures and instructions to all service personnel cover
5. No leads or components should touch a receiving tube or a resistorthe subject of X-rays in current T.V. receivers is the picture tube.
rated at 1 watt or more. Lead tension around protruding metal sur-However, this tube does not emit X-rays when the high voltage is
faces must be avoided.at the factory specified level. The proper value is given in the appli-
6. All critical components such as fuses, flameproof resistors, capaci-cable schematic. Operation at higher voltages may cause a failure
tors, etc. must be replaced with exact factory types. Do not useof the picture tube or high voltage supply and, under certain cir-
replacement components other than those specified or makecumstances, may produce radiation in excess of desirable levels.
unrecommended circuit modifications.2. Only factory specified C.R.T. anode connectors must be used.
7. After re-assembly of the set always perform an A.C. leakage testDegaussing shields also serve as X-ray shield in color sets.
on all exposed metallic parts of the cabinet, (the channel selectorAlways re-install them.
knob, antenna terminals, handle and screws) to be sure the set is3. It is essential that the serviceman has available an accurate and
safe to operate without danger of electrical shock. Do not use areliable high voltage meter. The calibration of the meter should be
line isolation transformer during this test. Use an A.C. voltmeter,checked perio - dically against a reference standard. Such as the
having 5000 ohms per volt or more sensitivity, in the followingone available at your distributor.
manner : connect a 1500 ohm 10 watt resistor, paralleled by a 154. When the high voltage circuitry is operating properly there is no
mfd. 150V A.C. type capacitor between a known good earthpossibility of an X-radiation problem. Every time a color chassis is
ground (9water pipe, conduit, etc.) and the exposed metallic parts,serviced, the brightness should be run up and down while monitor-
one at a time. Measure the A.C. voltage across the combination ofing the high voltage with a meter to be certain that the high voltage
1500 ohm resistor and 0.15 MFD capacitor. Reverse the A.C. plugdoes not exceed the specified value and that it is regulating cor-
and repeat A.C. voltage measurements for each exposed metallicrectly. We suggest that you and your service organization review
part. Voltage measured must not exceed 0.75 volts R.M.S. Thistest procedures so that voltage regulation is always checked as a
corresponds to 0.5 milliamp A.C. Any value exceeding this limitstandard servicing procedure. And that the high voltage reading be
constitutes a potential shock hazard and must be corrected imme-recorded on each customer?s invoice.
diately.5. When troubleshooting and making test measurements in a
receiver with a problem of excessive high voltage, avoid being
A.C. VOLTMETER
unnecessarily close to the picture tube and the high voltage compartment.
Do not operate the chassis longer than is necessary to locate the
cause of excessive voltage.
6. Refer to HV, B+and Shutdown adjustment procedures described in
the appropriate schematic and diagrams(where used).
0.15 uF
Good earth ground,
such as the water
1500 OHMPlace this probe
pipe, conduit, etc.
on each exposed
10WATTmetal part.
3 |
ACEC
DAEWOO
