Tektronix 310A, Instruction Manual, Page: 46 / 132

Maintenance-Type 310A
Visual Inspection
The Type 310A should be inspected occasionally for
such defects as broken connections, broken or damaged
ceramic strips, improperly seated tubes, and heat-damaged
parts.
The corrective procedure for most visible defects is
obvious; however, particular care must be taken if heat-
damaged components are found. Overheating usually
indicates other trouble in the instrument; therefore, it is
im portant that the cause o f overheating be corrected to
prevent recurrence o f the damage.
Tube Checks
Periodic checks o f the tubes in the Type 31OA are not
recommended. The best check o f tube performance is its
actual operation in the instrument. More details on check­
ing tube operation is given under Troubleshooting.
Recalibration
To assure accurate measurements, check the calibration
o f this instrument after each 500 hours o f operation or
every six months if used infrequently. In addition, replace­
ment o f components may necessitate recalibration o f the
affected circuits. Complete calibration instructions are
given in the Calibration section.
The calibration procedure can also be helpful in local­
izing certain troubles in the instrument. In some cases,
minor troubles may be revealed and/or corrected by recali­
bration.
TRO UBLESHO O TING
Introduction
The follow ing inform ation is provided to facilitate
troubleshooting o f the Type 310A. Inform ation contained
in other sections o f this manual should be used along w ith
the follow ing inform ation to aid in locating the defective
component. An understanding o f the circuit operation is
very helpful in locating troubles. See the C ircuit Descrip­
tion section fo r complete information.
Troubleshooting Aids
Diagrams. Complete circuit diagrams are given on fold-
out pages in the Diagrams section. The component number
and electrical value o f each component are shown on the
diagrams. Each main circuit is assigned a series o f compo­
nent numbers. Table 4-1 lists the main circuits in the Type
31 OA and the series o f component numbers assigned to
each. Im portant voltages and waveforms are also shown on
the diagrams.
TABLE 4-1
Component Numbers
Component numbers
on diagrams
Circuit
1-49 Sweep Trigger
101-179 Sweep Generator
201-249 Horizontal A m plifier
300-399 Vertical Preamplifier
400-480 Vertical A m plifier
500-549 Calibrator
600-675 Power Supply
700-760 CRT Circuit
Wiring Color-Code. A ll insulated wire and cable used in
the Type 310A is color-coded to facilitate circuit tracing.
Signal carrying leads are identified w ith one or tw o colored
stripes. Voltage supply leads are identified w ith three
stripes to indicate the approximate voltage using the EIA
resistor color code. A w hite background color indicates a
positive voltage and a tan background indicates a negative
voltage. The widest color stripe identifies the first color o f
the code. Table 4-2 gives the wiring color-code for the
power-supply voltages used in the Type 310A.
TABLE 4-2
Power Supply Wiring Color Code
Supply Background
Color
First
Stripe
Second
Stripe
Third
Stripe
—150 V o lt black brown green brown
+100 V o lt white brown black brown
+300 V o lt white orange black brown
+400 V o lt
(unreg.)
gray orange
red
Troubleshooting Equipment
The following equipment is useful for troubleshooting
the Type 31 OA.
1. M ultim eter
Description: Voltm eter, 20,000 ohms/volt and 0 to 500
volts range; ohmmeter, 0 to 50 megohms. Accuracy, w ithin
3%. Test probes must be insulated to prevent accidental
shorting.
Purpose. To check voltages and fo r general trouble­
shooting.
2. Test Oscilloscope
Description; DC to 5 MHz frequency response, 50 m illi­
volts to 50 volts/division deflection factor. A 10X probe
should be used to reduce circuit loading.
Purpose: To check waveforms.
4 -2