CHAPTER 1 GENERAL ADJUSTMENTS
SAFETY INSTRUCTIONS
WARNING: BEFORE SERVICING THIS CHASSIS, READ THE OX-RAY RADIATION PRECAUTION�, OSAFETY PRECAU-
TION� AND OPRODUCT SAFETY NOTICE� INSTRUCTIONS BELOW.
X-RAY RADIATION PRECAUTION
1. Excessive high voltage can produce potentially hazardous2. This receiver is equipped with a Fail Safe (FS) circuit which
X-RAY RADIATION. To avoid such hazards, the high volt-prevents the receiver from producing an excessively high
age must not be above the specified limit. The nominalvoltage even if the B+ voltage increases abnormally. Each
value of the high voltage of this receiver is (A) kV at zerotime the receiver is serviced, the FS circuit must be checked
beam current (minimum brightness) under a 120V ACto determine that the circuit is properly functioning, follow-
power source. The high voltage must not, under any cir-ing the FS CIRCUIT CHECK procedure in this manual.GENERAL ADJUSTMENTS
cumstances, exceed (B) kV.3. The only source of X-RAY RADIATION in this TV receiver
Refer to table-1 for high voltage (A), (B).is the picture tube. For continued X-RAY RADIATION pro-
tection, the replacement tube must be exactly the same
(See SETTING & ADJUSTING DATA on page 18)
type tube as specified in the parts list.
Each time a receiver requires servicing, the high voltage4. Some part in this receiver have special safety-related char-
should be checked following the HIGH VOLTAGE CHECKacteristics for X-RAY RADIATION protection. For contin-
procedure in this manual. It is recommended that the read-ued safety, parts replacement should be undertaken only
ing of the high voltage be recorded as a part of the serviceafter referring to the PRODUCT SAFETY NOTICE below.
record. It is important to use an accurate and reliable high
voltage meter.
SAFETY PRECAUTION
WARNING : Service should not be attempted by anyone unfa-Connect a 1500 ohm 10 watt resistor, paralleled by a 0.15
miliar with the necessary precautions on this receiver. The fol-?F, AC type capacitor, between a known good earth ground
lowing are the necessary precautions to be observed before(water pipe, conduit, etc.) and the exposed metallic parts,SPECIFIC INFORMATIONS
servicing this chassis.one at a time. Measure the AC voltage across the combi-
1. An isolation Transformer should be connected in the powernation of 1500 ohm resistor and 0.15 ?F capacitor. Re-
line between the receiver and the AC line before any serv-verse the AC plug at the AC outlet and repeat AC voltage
ice is performed on the receiver.measurements for each exposed metallic part. Voltage
2. Always discharge the picture tube anode to the CRT con-measured must not exceed 0.675 volts rms. This corre-
ductive coating before handling the picture tube. The pic-sponds to 0.45 milliamp. AC. Any value exceeding this limit
ture tube is highly evacuated and if broken, glass fragmentsconstitutes a potential shock hazard and must be corrected
will be violently expelled. Use shatter proof goggles andimmediately.
keep picture tube away from the unprotected body while
handling.AC VOLTMETER
3. When replacing a chassis in the cabinet, always be cer-
tain that all the protective devices are put back in place,
such as; non-metallic control knobs, insulating covers,
shields, isolation resistor-capacitor network etc.
4. Before returning the set to the customer, always perform
an AC leakage current check on the exposed metallic parts
of the cabinet, such as antennas, terminals, screwheads,0.15?F
metal overlays, control shafts etc. to be sure the set is safe
Place this probe on
to operate without danger of electrical shock. Plug the AC
line cord directly into a 120V AC outlet (do not use a lineGood earth groundeach exposed
isolation transformer during this check). Use an AC volt-such as a watermetallic part.
pipe, conduit, etc.
meter having 5000 ohms per volt or more sensitivity in the1500 ohm
following manner:10 watt
PRODUCT SAFETY NOTICE
Many electrical and mechanical parts in this chassis have special safety-related characteristics. These characteristics are
often passed unnoticed by a visual inspection and the protection afforded by them cannot necessarily be obtained by using
replacement components rated for higher voltage, wattage, etc. Replacement parts which have these special safety charac-
teristics are identified in this manual and its supplements; electrical components having such features are identified by the
international hazard symbols on the schematic diagram and the parts list.
Before replacing any of these components, read the parts list in this manual carefully. The use of substitute replacement
parts which do not have the same safety characteristics as specified in the parts list may create shock, fire, X-ray radia-
tion or other hazards.
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ACEC
