Section
6-2225
Service
MAINTENANCE
This section contains information for conducting board removal procedures are included in the
preventive maintenance, troubleshooting, and corrective maintenance part of this section.
corrective maintenance on the instrument. Circuit
STATIC-SENSITIVE COMPONENTS
The following precautions are applicable when
performing any maintenance involving internal
access to the instrument.
Static discharge can damage any semi-
conductor component in this instrument.
This instrument contains electrical components that
are susceptible to damage from static discharge.
Table 6-1 lists the relative susceptibility of various
classes of semiconductors. Static voltages of 1 KV
to
30
KV are common in unprotected environments.
When performing maintenance, observe the
following precautions to avoid component damage:
1
.
Minimize handling of static-sensitive
components.
2.
Transport and store static-sensitive compo-
nents or assemblies in their original containers
or on a metal rail. Label any package that
contains static-sensitive components or
assemblies.
3.
Discharge the static voltage from your body by
wearing a grounded antistatic wrist strap while
handling these components. Servicing static-
sensitive components or assemblies 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.
Table
6-1
Relative Susceptibility to Static-Discharge
Damage
I
MOS or CMOS microcircuits or
discretes, or linear microcircuits
with MOS inputs (Most Sensi-
tive)
I
Semiconductor Classes
Relative
Susceptibility
Levelsa
ECL
2
Schottky signal diodes
I
I
3
Schottky
TTL
I
I
4
High-frequency bipolar
transistors
1
=
100 to 500
V
6
=
600 to 800 V
2
=
200 to 500 V
7
=
400 to 1000 V (est)
3
=
250 V 8
=
900 V
4
=
500 V
9
=
1200 V
5
=
400 to 600
V
I
5
I
JFET
Linear microcircuits
Low-power Schottky
TrL
TTL
(Least Sensitive)
5.
Keep the component leads shorted together
whenever possible.
6.
Pick up components by their bodies, never by
their leads.
6
7
8
9
Scans
by
ARTEK
MEDLQ
-
avoitage equivalent for levels (voltage discharged
from a
100-pF capacitor through a resistance of
100
a):
To Next Page
Loading...