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Complete Performance Check and Adjustment instruc
tions are given in Sections 4 and 5. The Performance Check
Procedure can also be helpful in localizing certain trouble in
the instrument. In some cases, minor problems may be re
INTRODUCTION
Preventive maintenance performed on a regular basis
should reveal most potential problems before an instrument
malfunctions. However, should troubleshooting be required,
the following information is provided to facilitate location of
a fault. In addition, the material presented in the "Theory of
Operation" and the "Diagrams" sections of this manual may
be helpful while troubleshooting.
TROUBLESHOOTING AIDS
Schematic Diagrams
Complete schematic diagrams are located on tabbed
foldout pages in the "Diagrams" section. The portions of
circuitry that are mounted on each circuit board are en
closed within heavy black lines. Also within the black lines,
near either the top or the bottom edge, are the assembly
number and name of the circuit board.
Component numbers and electrical values of compo
nents in this instrument are shown on the schematic dia
grams. Refer to the first page of the "Diagrams" section for
definitions of the reference designators and symbols used to
identify components.
Circuit Board Illustrations
Circuit board illustrations (showing the physical location
of each component) are provided for use in conjunction with
each schematic diagram. Each board illustration can be
found on the back side of a foldout page, preceding the
schematic diagram(s) to which it relates. If more than one
schematic diagram is associated with a particular circuit
board, the board illustration is located on a left-hand page
preceding the diagram with which the board is first
associated.
Also provided in the " Diagrams" section is an illustration
of the bottom side of the Main circuit board. This drawing
facilitates troubleshooting by showing the connection pads
and the location of components that are mounted on the top
side of the board. Probing of Main board component signals
that are inaccessible from the top side can be achieved with
vealed or corrected by readjustment. If only a partial adjust
ment is performed, see the interaction chart, Table 5-1, for
possible adjustment interactions with other circuits.
TROUBLESHOOTING
out the necessity of disassembling portions of the
instrument.
Waveform test-point locations are also identified on the
circuit board illustration by hexagonal-outlined numbers that
correspond to the waveform numbers appearing on both the
schematic diagram and the waveform illustration.
Circuit Board Locations
An illustration depicting the location of a circuit board
within the instrument is shown on the foldout page adjacent
to the circuit board illustration.
Circuit Board Interconnection Diagram
A circuit board cable distribution diagram and connector-
pin locator table is also provided in the "Diagrams" section
to aid in tracing a signal path or power source between
boards. All wires, plug and jack numbers are shown along
with wire or pin numbers.
Power Distribution Diagram
A Power Distribution diagram 8 is provided to aid in trou
bleshooting power-supply problems. This diagram shows
service jumpers used to remove power from the various cir
cuit boards. Excessive loading on a power supply by a cir
cuit board can be isolated to the faulty board by
disconnecting appropriate service jumpers.
Grid Coordinate System
Each schematic diagram and circuit board illustration has
a grid border along its left and top edges. A table located
adjacent to each schematic diagram lists the grid coordi
nates of each component shown on that schematic. To aid
in physically locating a component on the respective circuit
board, this table also lists the circuit-board grid coordinate
of each component.
Adjacent to each circuit board illustration is an alphanu
meric listing of every component mounted on that board. A
second column in this listing identifies the schematic dia-
Maintenance— 2215A Service
6-5
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Table of Contents
Troubleshooting
