| CAUTION: Before servicing
receivers covered by this service manual and
its supplements and addenda, read and follow
the SAFETY PRECAUTIONS of this publication.
Remember: Safety First. General Guidance
An isolation Transformer should always be
used during the servicing of a receiver
whose chassis is not isolated from the AC
power line.
Use a transformer of adequate power
rating as this protects the technician from
accidents resulting in personal injury from
electrical shocks. It will also protect the
receiver and it's components from being
damaged by accidental shorts of the
circuitry that may be inadvertently
introduced during the service operation.
If any fuse (or Fusible Resistor) in this
TV receiver is blown, replace it with the
specified.
When replacing a high wattage resistor (Oxide
Metal Film Resistor, over 1W), keep the
resistor 10mm away from PCB.
Keep wires away from high voltage or high
temperature parts.
General Servicing Precautions
1. Always unplug the receiver AC power cord
from the AC power
source before;
a. Removing or reinstalling any component,
circuit board
module or any other receiver assembly.
b. Disconnecting or reconnecting any
receiver electrical plug or
other electrical connection.
c. Connecting a test substitute in parallel
with an electrolytic
capacitor in the receiver.
CAUTION: A wrong part substitution or
incorrect polarity
installation of electrolytic capacitors may
result in an
explosion hazard.
2. Test high voltage only by measuring it
with an appropriate high
voltage meter or other voltage measuring
device (DVM,
FETVOM, etc) equipped with a suitable high
voltage probe.
Do not test high voltage by "drawing an arc".
3. Do not spray chemicals on or near this
receiver or any of its
assemblies.
4. Unless specified otherwise in this
service manual, clean
electrical contacts only by applying the
following mixture to the
contacts with a pipe cleaner, cotton-tipped
stick or comparable
non-abrasive applicator; 10% (by volume)
Acetone and 90% (by
volume) isopropyl alcohol (90%-99% strength)
CAUTION: This is a flammable mixture.
Unless specified otherwise in this service
manual, lubrication of
contacts in not required.
5. Do not defeat any plug/socket B+
voltage interlocks with which
receivers covered by this service manual
might be equipped.
6. Do not apply AC power to this
instrument and/or any of its
electrical assemblies unless all solid-state
device heat sinks are
correctly installed.
7. Always connect the test receiver
ground lead to the receiver
chassis ground before connecting the test
receiver positive
lead.
Always remove the test receiver ground lead
last.
8. Use with this receiver only the test
fixtures specified in this
service manual.
CAUTION: Do not connect the test fixture
ground strap to any
heat sink in this receiver. |
