Troubleshooting; Relative Susceptibility To Static Discharge Damage - Tektronix 7B53A Instruction Manual

Maintenance-7B53A/7B53AN
Table 5-1 for relative susceptibility of various classes of
semiconductors. Static voltages of 1 kV to 30 kV are
common in unprotected environments.
Observe the following precautions to avoid damage:
1. Minimize handling of static-sensitive components.
2. Transport and store static-sensitive components or
assemblies in their original containers, on a metal rail,
or on conductive foam. label any package that con-
tai ns static-sensitive assem blies or com ponents.
3. Dischargethe static voltage from your body by weari ng
a wrist strap while handling these components. Ser-
vicing static-sensitive assemblies or components
should be performed only at a static-free work station
by qualified service personnel.
4. Nothing capable of generating or holding a static
charge should be allowed on the work station surface.
5. Keep the component leads shorted together whenever
possible.
6. Pick up components by the body, never by the leads.
7. Do not slide the components over any surface.
8. Avoid handling components in areas that have a floor
or work-surface coveri ng capable of generati ng a static
charge.
9. Use a solderi ng iron that is con nected to earth ground.
10. Use only special antistatic suction type or wick type
desolderi ng tools.
Before using any test equipment to make measure-
ments on static-sensitive components or assemblies, be
certain that any voltage or current supplied by the test
equipment does not exceed the limits of the component to
be tested.
5-2
Table 5-1
RELATIVE SUSCEPTIBILITY TO
STATIC DISCHARGE DAMAGE
Semiconductor Classes
MOS or CMOS microcircuits or
discretes, or linear microcircuits
with MOS inputs (Most Sensitive)
ECl
Schottky signal diodes
Schottky TTL
High-frequency bipolar transistors
JFETS
Linear microcircuits
low-power Schottky TTL
TTL (least Sensitive)
'Voltage equivalent for levels:
1
=
100 to 500 V 4
=
500 V
2 = 200 to 500 V 5 = 400 to 600 V
3 = 250 V 6
=
600 to 800 V
Relative
Susceptibility
Levels'
1
2
3
4
5
6
7
8
9
7
=
400 to 1000 V (est)
8 = 900 V
9
=
1200 V
(Voltage discharged from a 100 pF capacitor through a resistance
of 100 ohms.)
TROUBLESHOOTING
Introduction
The following information is provided to facilitate
troubleshooting of the 7B53A17B53AN. Information con-
tained in other sections of this manual should be used
along with the following information to aid in locating the
defective component. An understanding of the circuit
operation is very helpful in locating troubles. See the
Circuit Operation in Section 3.
Troubleshooting Aids
Diagrams. Circuit diagrams are given on foldout pages
in Section 8. The component number and electrical value
of each component in this instrument are shown on the
diagrams.
Circuit Boards. Fig. 8-2 (located in the Diagrams sec-
tion) shows the location of the circuit boards within this in-
strument along with the assembly numbers. The assembly
numbers are used on the diagrams to aid in locating the
boards. Pictures of the circuit boards are shown in the Dia-
grams section, on the back of the page opposite the circuit
REV JUL 1986