The following items should be checked for continued protection of the customer and the service technician.
Leakage current check
Before returning the set to the customer, be sure to carry out either (1) a leakage current check or (2) a line to chassis resistance check. If the leakage current exceeds 0.5 milliamps, or if the resistance from chas-
sis to either side of the power cord is less than 460 kohms, the set is defective.
Be sure to test for leakage current with the AC plug in both polarities, in addition, when the set's power is in each state (on, off and standby mode), if applicable.
CAUTION Please heed the following cautions and instructions during servic-
ing and inspection.
◎ Heed the cautions!
Cautions which are delicate in particular for servicing are labeled on the cabinets, the parts and the
chassis, etc. Be sure to heed these cautions and the cautions described in the handling instructions.
◎ Cautions concerning electric shock!
(1) An AC voltage is impressed on this set, so if you touch internal metal parts when the set is energized,
you may get an electric shock. Avoid getting an electric shock, by using an isolating transformer and
wearing gloves when servicing while the set is energized, or by unplugging the power cord when
replacing parts, for example.
(2) There are high voltage parts inside. Handle with extra care when the set is energized.
◎ Caution concerning disassembly and assembly!
Through great care is taken when parts were manufactured from sheet metal, there may be burrs on the
edges of parts. The burrs could cause injury if fingers are moved across them in some rare cases. Wear
gloves to protect your hands.
◎ Use only designated parts!
The set's parts have specific safety properties (fire resistance, voltage resistance, etc.). Be sure to use
parts which have the same properties for replacement. The burrs have the same properties. In particular,
for the important safety parts that are indicated by the
z
mark on schematic diagrams and parts lists,
be sure to use the designated parts.
◎ Be sure to mount parts and arrange the wires as they were originally placed!
For safety seasons, some parts use tapes, tubes or other insulating materials, and some parts are mount-
ed away from the surface of printed circuit boards. Care should also be taken with the positions of the
wires by arranging them and using clamps to keep them away from heating and high voltage parts, so
be sure to set everything back as it was originally placed.
◎ Make a safety check after servicing!
Check that all screws, parts and wires removed or disconnected when servicing have been put back
in their original positions, check that no serviced parts have deteriorated the area around. Then make
an insulation check on the external metal connectors and between the blades of the power plug. And
otherwise check that safety is ensured.
(Insulation check procedure)
Unplug the power cord from the power outlet, disconnect the antenna, plugs, etc., and on the power.
Using a 500V insulation resistance tester, check that the insulation resistance value between the inplug
and the externally exposed metal parts (antenna terminal, headphones terminal, input terminal, etc.) is
1M Ω or greater. If it is less, the set must be inspected and repaired.
Many of the electric and the structural parts used in the set have special safety properties. In most cases
these properties are difficult to distinguish by sight, and the use of replacement parts with higher rat-
ings (rated power and withstand voltage) does not necessarily guarantee that safety performance will
be preserved. Parts with safety properties are indicated as shown below on the wiring diagrams and the
parts list in this service manual. Be sure to replace them with the parts which have the designated part
number.
(1) Schematic diagrams
Indicated by the
z
mark.
(2) Parts lists
Indicated by the
z
mark.
The use of parts other than the designated parts could cause electric shocks, fires or other dangerous
situations.
CAUTION Concerning important safety parts
SAFETY PRECAUTIONS
Before Servicing
This Unit
Electrical
Mechanical
Repair Information
Updating
3
