SAFETY INSTRUCTIONS
SAFETY PRECAUTIONS
READING SHOULD NOT EXCEED 1400 mV.
WARNING: The chassis of this receiver has a floating groundAC VOLTMETER
with the potential of one half the AC line voltage in respect to(5000 ohms per volt or more sensitivity)
earth ground. Service should not be attempted by anyone not
familiar with the precautions necessary when working on this
type of equipment.
The following precautions must be observed:
TELEVISION
1. An isolation transformer must be connected in the power lineRECEIVER
between the receiver and the AC line before any service is
performed on the receiver.
Good earth ground
2. Comply with all caution and safety-related notes provided on2000 ohmsuch as a water pipe,
the side of the cabinet, inside the cabinet, on the chassis, and10 wattconduit, etc.
the picture tube.
3. When replacing a chassis in the cabinet, always be certain
that all the protective devices are installed properly, such as
control knobs, adjustment covers, shields and barriers.
DO NOT OPERATE THIS TELEVISION RECEIVER AC OUTLET
To be touched to all of exposed metal parts.
WITHOUT THE PROTECTIVE SHIELD IN POSITION AND
PROPERLY SECURED.Voltmeter Hook-up for Leakage Current Check.
4. Before replacing the back cover of the set, thoroughly inspect
the inside of the cabinet to see that no stray parts or tools
have been left inside.X-RADIATION PRECAUTION
The primary source of X-RADIATION in solid-state receivers is the
Before returning any television to the customer, the
service technician must perform the following safety checkspicture tube. The picture tube is specially constructed to limit X-Ray
emission. For continued X-RADIATION protection, the replacement
to be sure that the unit is completely safe to operate without
danger of electrical shock.tube must be the same type as the original (including the suffix let-
ter in the part numbers). Excessive high voltage may produce
ANTENNA COLD CHECKpotentially hazardous X-RADIATION. avoid such hazards, theTo
Remove AC plug from the 220 VAC outlet and place a jumperhigh voltage must be maintained withicific limits. Refer to the X-n spe
across the two blades. Connect one lead of an ohmmeter to theRADIATION WARNING NOTE on the CHASSIS SCHEMATIC in
jumpered AC plug, and touch the other lead to each exposedthis service manual for specific high voltage limits. If the high volt-
antenna terminal (UHF and VHF antenna terminals). The resis-age exceeds specified limits, check the components specified on
tance must measure 10M ohm or over. Any resistance valuethe chassis schematic diagram and take the necessary corrective
below this range indicates an abnormality which requires correc-action. Carefully follow the instructions for the +B Voltage Check
tive action.and the High Voltage Check to maintain the high voltage within the
specified limits.
LEAKAGE CURRENT CHECK
Plug the AC line cord directly into a 220 VAC outlet. (Do not usePRODUCT SAFETY NOTICE
an isolation transformer for this check.) Use an When replacing components in a receiverAC voltmeter,, always keep in mind
that has 5000 ohms per volt or more sensitivity. Connect a 2000the necessary product safety precautions. Pay special attention
ohm 10 watt resistor, between a known good earth groundto the replacement of components marked with a star ( ) in the
(water pipe, conduit, etc.) and all exposed metal parts of theparts list and in the schematic diagrams. To ensure safe product
cabinet (antennas, earphone jack, screwheads, metal overlays,operation, it is necessary to replace those components with the
control shafts, etc.). Measure the AC voltage across the 2000exact same PARTS.
ohm resistor.
The AC voltage should not exceed 1400 mV. A reading exceed-
ing 1400 mV indicates that a dangerous potential exists. The
fault must be located and corrected. Repeat the above test with
the receiver power plug reversed.
NEVER RETURN A RECEIVER TO THE CUSTOMER
WITHOUT TAKING THE NECESSARY CORRECTIVE
ACTION.
N 2 N |
ACEC
