Periodic Readjustment; Troubleshooting; Introduction; Troubleshooting Aids - Tektronix 2235A Instruction Manual

Maintenance
-
2235A
Instruction
PERIODIC READJUSTMENT
Complete Performance Check and Adjustment instruc-
tions are given in Sections 4 and 5. The Performance
Check Procedure can also be helpful in localizing
T o ensure accurate measurements, check the per-
certain troubles in the instrument. In some cases, minor
formance of this instrument every 2000 hours of problems may be revealed or corrected by readjust-
operation, or if used infrequently, once each year. In ment. If only a partial adjustment is performed, see the
addition, replacement of components may necessitate interaction chart, Table 5-1, for possible adjustment
readjustment of the affected circuits.
interaction with other circuits.
TROUBLESHOOTING
INTRODUCTION
Preventive maintenance performed on a regular basis
should reveal most potential problems before an instru-
ment malfunctions. However, should troubleshooting be
required, the following information is provided to facili-
tate location of afault. In addition, the material presented
in the Theory of Operation and Diagrams sections of this
manual may be helpful while troubleshooting.
TROUBLESHOOTING AIDS
Also provided in the Diagrams section is an illustration of
the bottom side of the Main circuit board. This illustration
aids in troubleshooting by showing the connection pads
for the components mounted on the top side of the circuit
board. By using this illustration, circuit tracing and
probing for voltages and signals that are inaccessible
from the top side of the board may be achieved without
dismantling 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.
Schematic Diagrams
Complete schematic diagrams are located on tabbed
Circuit Board Locations
foldout pages in the Diagrams section. Portions of
circuitry mounted
OCl
each circuit board are enclosed by
An illustration depicting the location of a circuit board
heavy black lines. The assembly r ~ m b e r and of
within the instrument is shown on the foldout page
the circuit are shown near either the top O r the bottom
adjacent to the circuit board illustration.
edge of the enclosed area.
Component numbers and electrical
V ~ ~ U ~ S
of COm-
Circuit Board Interconnections
ponents in this instrument are shown on the schematic
diagrams. Refer to the first page of the Diagrams section
for the reference designators and symbols used to iden-
A circuit board interconnection diagram is provided in
tify components.
the Diagrams section to aid in tracing a signal path or
power source between boards. All wire, plug, and jack
Circuit Board Illustrations
numbers are shown along with their associated wire or
pin numbers.
Circuit board illustrations showing the physical location
of each component are provided for use in conjunction
Power Distribution
with each schematic diagram. Each board illustration is
found in the Diagrams section on the back of a foldout
Power Distribution diagram 11 is provided to aid in
page, preceding the first schematic diagram(s) to which
troubleshooting power-supply problems. This diagram
it relates. If more than one schematic diagram is associ-
shows the service jumper connections used to remove
ated with a particular circuit board, the board illustration
power from the various circuit boards. Excessive loading
is located on a left-hand page preceding the diagram
on a power supply by a circuit board fault may be iso-
with which the board is first associated.
lated by disconnecting the appropriate service jumpers.