SERVICING PRECAUTIONS
SERVICING PRECAUTIONS
CAUTION: Before servicing receivers covered by this service
CAUTION: Before servicing receivers covered by this service
manual and its supplements and addenda, read and follow the
manual and its supplements and addenda, read and follow the
SAFETY PRECAUTIONS
SAFETY PRECAUTIONS
on page 3 of this publication.
on page 3 of this publication.
NOTE
NOTE
: If unforeseen circumstances create conict between the
: If unforeseen circumstances create conict between the
following servicing precautions and any of the safety precautions
following servicing precautions and any of the safety precautions
on page 3 of this publication, always follow the safety precautions.
on page 3 of this publication, always follow the safety precautions.
Remember: Safety First.
Remember: Safety First.
General Servicing Precautions
General Servicing Precautions
1. Always unplug the receiver AC power cord from the AC power
1. Always unplug the receiver AC power cord from the AC power
source before;
source before;
a. Removing or reinstalling any component, circuit board mod-
a. Removing or reinstalling any component, circuit board mod-
ule or any other receiver assembly.
ule or any other receiver assembly.
b. Disconnecting or reconnecting any receiver electrical plug or
b. Disconnecting or reconnecting any receiver electrical plug or
other electrical connection.
other electrical connection.
c. Connecting a test substitute in parallel with an electrolytic
c. Connecting a test substitute in parallel with an electrolytic
capacitor in the receiver.
capacitor in the receiver.
CAUTION
CAUTION
: A wrong part substitution or incorrect polarity
: A wrong part substitution or incorrect polarity
installation of electrolytic capacitors may result in an explo-
installation of electrolytic capacitors may result in an explo-
sion hazard.
sion hazard.
2. Test high voltage only by measuring it with an appropriate
2. Test high voltage only by measuring it with an appropriate
high voltage meter or other voltage measuring device (DVM,
high voltage meter or other voltage measuring device (DVM,
FETVOM, etc) equipped with a suitable high voltage probe.
FETVOM, etc) equipped with a suitable high voltage probe.
Do not test high voltage by "drawing an arc".
Do not test high voltage by "drawing an arc".
3. Do not spray chemicals on or near this receiver or any of its
3. Do not spray chemicals on or near this receiver or any of its
assemblies.
assemblies.
4. Unless specied otherwise in this service manual, clean
4. Unless specied otherwise in this service manual, clean
electrical contacts only by applying the following mixture to the
electrical contacts only by applying the following mixture to the
contacts with a pipe cleaner, cotton-tipped stick or comparable
contacts with a pipe cleaner, cotton-tipped stick or comparable
non-abrasive applicator; 10 % (by volume) Acetone and 90 %
non-abrasive applicator; 10 % (by volume) Acetone and 90 %
(by volume) isopropyl alcohol (90 % - 99 % strength)
(by volume) isopropyl alcohol (90 % - 99 % strength)
CAUTION
CAUTION
: This is a ammable mixture.
: This is a ammable mixture.
Unless specied otherwise in this service manual, lubrication of
Unless specied otherwise in this service manual, lubrication of
contacts in not required.
contacts in not required.
5. Do not defeat any plug/socket B+ voltage interlocks with which
5. Do not defeat any plug/socket B+ voltage interlocks with which
2. After removing an electrical assembly equipped with ES
2. After removing an electrical assembly equipped with ES
devices, place the assembly on a conductive surface such as
devices, place the assembly on a conductive surface such as
aluminum foil, to prevent electrostatic charge buildup or expo-
aluminum foil, to prevent electrostatic charge buildup or expo-
sure of the assembly.
sure of the assembly.
3. Use only a grounded-tip soldering iron to solder or unsolder ES
3. Use only a grounded-tip soldering iron to solder or unsolder ES
devices.
devices.
4. Use only an anti-static type solder removal device. Some solder
4. Use only an anti-static type solder removal device. Some solder
removal devices not classied as “anti-static” can generate
removal devices not classied as “anti-static” can generate
electrical charges sufcient to damage ES devices.
electrical charges sufcient to damage ES devices.
5. Do not use freon-propelled chemicals. These can generate
5. Do not use freon-propelled chemicals. These can generate
electrical charges sufcient to damage ES devices.
electrical charges sufcient to damage ES devices.
6. Do not remove a replacement ES device from its protective
6. Do not remove a replacement ES device from its protective
package until immediately before you are ready to install it.
package until immediately before you are ready to install it.
(Most replacement ES devices are packaged with leads electri-
(Most replacement ES devices are packaged with leads electri-
cally shorted together by conductive foam, aluminum foil or
cally shorted together by conductive foam, aluminum foil or
comparable conductive material).
comparable conductive material).
7. Immediately before removing the protective material from the
7. Immediately before removing the protective material from the
leads of a replacement ES device, touch the protective material
leads of a replacement ES device, touch the protective material
to the chassis or circuit assembly into which the device will be
to the chassis or circuit assembly into which the device will be
installed.
installed.
CAUTION
CAUTION
: Be sure no power is applied to the chassis or circuit,
: Be sure no power is applied to the chassis or circuit,
and observe all other safety precautions.
and observe all other safety precautions.
8. Minimize bodily motions when handling unpackaged replace-
8. Minimize bodily motions when handling unpackaged replace-
ment ES devices. (Otherwise harmless motion such as the
ment ES devices. (Otherwise harmless motion such as the
brushing together of
brushing together of
your clothes fabric or
your clothes fabric or
the lifting
the lifting
of your
of your
foot from a carpeted oor can generate static electricity suf
foot from a carpeted oor can generate static electricity suf
-
-
cient to damage an ES device.)
cient to damage an ES device.)
General Soldering Guidelines
General Soldering Guidelines
1. Use a grounded-tip, low-wattage soldering iron and appropriate
1. Use a grounded-tip, low-wattage soldering iron and appropriate
tip size and shape that will maintain tip temperature within the
tip size and shape that will maintain tip temperature within the
range or 500 °F to 600 °F.
range or 500 °F to 600 °F.
2. Use an appropriate gauge of RMA resin-core solder composed
2. Use an appropriate gauge of RMA resin-core solder composed
of 60 parts tin/40 parts lead.
of 60 parts tin/40 parts lead.
3. Keep the soldering iron tip clean and well tinned.
3. Keep the soldering iron tip clean and well tinned.