Model 182C
Service
SECTION VIII
SCHEMATICS AND TROUBLESHOOTING
8-1. INTRODUCTION.
8-2.
This section
contains schematics,
repair and replace-
ment information,
component
identification illustrations,
and
troubleshooting and
repair information.
Table
8
1
defines symbols and
conventions used on the
schematics.
The overall
block diagram is located
in Section IV.
8-3.
SCHEMATICS.
8-4. Schematic
diagrams appear
on
right hand
pages
that unfold
outside the right edge of
the manual.
This
allows
viewing the
schematics while referring to text
and
figures in
another section of the
manual.
8-5 The schematics are
drawn primarily to show
the
electronic
function of the circuit and
instrument. A
given
schematic may include
all or part of
several assemblies.
Schematics
also include dc
voltages
and waveforms at
helpful points.
Information explaining
the symbols and
conventions
used in these
schematics is provided by
Table
8-1. Voltage
measurement conditions applicable to
each
schematic are shown next to the
schematic.
8-6.
Each
schematic is
identified
by
a code
number.
The number of the
schematic is located in the
lower right
hand corner
near the figure
number and
title. These
numbers
are used to make it easy
to trace a
circuit that
begins on one
schematic and is continued
on another.
When a circuit
leaves a
schematic
it is
identified
with the
code
number of the
schematic on which it is continued.
Both schematics have the same circuit
identification infor-
mation such as voltage,
function or circuit
connection
8-7.
REFERENCE DESIGNATIONS
.
8-8. The unit
system
of reference
designations used in
this manual Is in accordance with provisions of the
USA
Standard Reference
Designations for Electrical and Elec-
tronic
Parts and Equipments dated March
1,
1968. Minor
variations due to design and manufacturing practices not
specifically covered
by
the standard
may
be noted.
8-9.
Each electrical component is identified
by a
class
letter and number. This letter-number combination is the
basic designation for each component. Components That
are separately replaceable and are part of an assembly
have, in addition
to
the
basic
designation,
a
prefix
desig-
nation indicating the assembly on which
the component
Is physically located. Components not located on an
assembly will have only the basic designation and are
listed in the replaceable parts
list (Section VI)
under
chassis parts.
8.10.
All components within
the shaded areas on the
schematics are
physically located on an etched circuit
board and should be prefixed
with the assembly number
assigned
to the
board
(e.g. resistor
R23
on assembly
A3
is referred
to as A3R23).
There
may also be an
R23
on
several other assemblies,
but
the
assembly designation
will always be different
(A2R23, A1
R23,
etc.).
8-11.
COMPONENT
LOCATION .
8-12. All adjustments are shown
in Section V,
and
mechanical and miscellaneous electrical parts are
shown
on
exploded
view drawings
in
Section VI. For ready
reference,
circuit assembly photographs are placed
ad-
jacent to the associated schematics.
8-13. Circuit
assembly photographs are subdivided
by a
grid, and components
within
each
subdivision are indexed
to
a
location table
below
the photograph.
A component
can be easily located on the photograph
by
first
referring
to the table. However, reference
designators
are not complete on the assembly photographs.
For the
complete reference designator, prefix the
assembly des-
ignation
given in the photograph to each component
designator.
8-14. TROUBLESHOOTING.
8-15.
The most important prerequisite for successful
troubleshooting is understanding how the
instrument
operates and correct usage of controls.
8-16.
Equipment troubles are frequently due
simply to
improper front-panel
control settings. Refer to the oper.
ating instructions in Section III for
a
complete
explan-
ation of each control's function along with
typical
operating instructions if in
doubt. Use
the
controls as a
guide
to
help isolate
a
trouble
to a specific area of
The
instrument.
8-17.
Troubleshooting
is
easier if
more
than
one
symptom
of a trouble is evident. Observe the instrument, and
note
all indications of faulty operation. If symptoms
indicate
more than one trouble, treat each problem
individually
and locate one Trouble at a time. Don't waste time
making
random checks.
Follow the procedure presented
here,
and
refer to other areas of information in
this manual if
necessary.
8-18.
Make a
thorough
check of instrument performance.
A complete procedure is given In Section V, and forms
are incluoed
to
record
results. A trouble, such
as
incorrect vertical
gain or sweep speed, may be
due to
lack of calibration.
8-1
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