Corrective Maintenance; Obtaining Replacement Parts - Tektronix CURVE-TRACER 576 Instruction Manual

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Maintenance-Type 576
TABLE
4-7
Supply Voltages When One
Supply is Shorted to Ground
Shorted Supply Voltages (Approximate)
Supply
-75
-12.5 +12.5 +100
-75 0 0 1 3
-12.5 -35 0 1.5 3
+12.5
-75
0 0 +100
+100 -75
-1
1.5 0
+225
-75 -12.5
5 8
-4 kV -75 -12.5 5
8
4.5 -75 -12.5
+12.5 +100
+5
-75
-12.5 +12.5 +100
+15 -75 -12.5 +12.5
+100
controls (be sure to note the effects of the MODE switch,
DISPLAY OFFSET Selector switch and STEP MULT .1X
button). When the proper readout has been determined,
locate the pins on the Readout Logic circuit board which
must be low to cause that readout (see Tables 4-3 through
4-6). When the proper states of the inputs and outputs of
the decoders have been determined, check these levels with
a voltmeter. A Type 576 READOUT EXTENDER (Tek-
tronix Part No. 067-0603-00) is available to aid in trouble-
shooting the readout.
1. If the inputs to the decoders are incorrect, something
is wrong with one of the cam switches.
2. If the inputs to the decoders are correct, but the
outputs are incorrect, the decoders are malfunctioning.
Supply
TABLE 4-8
Power Supply
Resistance Check
1
VOM Scale Resistance
Leads+ Leads-
-75 1 k~ 1.5 k 1.9 k
+100
1
k~
5k 1.8 k
+15 1
k~
23 k
2k
+225
1 k~ 36 k 12 k
-12.5
10~
25
~
35
~
+12.5
10
~
16
~
31
~
+5
10 ~ 28 ~ 90
~
+4.5
2
10
~
35
~
100
~
1
Type 5 76 turned off.
2
READOUT ILLUM control fully clockwise.
3. If the outputs of the decoders are correct, something
is wrong with a fiber-optic and lamp assembly (probably a
burned out lamp).
See the section of the Circuit Description on readout for
further information and an example of the operation of the
readout system.
+225 -4kV +4.5
+5 +15
0 0 0
0.5 1
0
0
1 1 1
0 0 0
0
1.5
0 0 0 0 0
0 0
2 3 6
0 0 2 3 6
+225
-4 kV
0
+5
+15
+225 -4 kV +4.5
0 +15
+225
-4 kV
+4.5 +5 0
Power Supply. A malfunction in the power supply is
often caused by one or more supplies being shorted to
ground. Table 4-7 indicates the states of all the power
supplies in the instrument when one of them is shorted to
ground. This table does not give values in cases when more
than one supply is shorted to ground or when one supply is
shorted to another supply. In these cases, the table only
indicates interrelationships between supplies. Table 4-8
gives resistance values of the supplies to ground as measured
by a VOM. Be sure the instrument is turned off when
making these measurements.
CORRECTIVE MAINTENANCE
General
Corrective maintenance consists of component replace-
ment and instrument repair. Special techniques required to
replace components in this instrument are given here.
Obtaining Replacement Parts
Staodard Parts. All electrical and mechanical part
replacements for the Type 576 can be obtained through
your local Tektronix Field Office or representative. How-
ever, many of the standard electronic components can be
obtained locally in less time than is required to order them
from Tektronix, Inc. Before purchasing or ordering replace-
ment parts, check the parts list for value, tolerance, rating
and description.
NOTE
When selecting replacement parts, it is important to
remember that the physical size and shape of a com-
ponent may affect its performance, particularly at the
upper frequency limits of the instrument. All replace-
ment parts should be direct replacements unless it is
known that a different component will not adversely
affect instrument performance.
Special Parts. In add it ion to the standard electronic
components, some special parts are used in the Type 576.
These parts are manufactured or selected by Tektronix, Inc.
to meet specific performance requirements, or are manufac-
4-9