Maintenance; Static-Sensitive Components; Relative Susceptibility To Static-Discharge D A M A G E - Tektronix 2246 1Y Service Manual

This section of the manual contains information for
conducting preventive
shooting, and corrective maintenance on the 2246
1Y and 2246 Mod A Oscilloscope. General infor­
mation regarding the care and handling of the semi­
conductor devices that can be damaged by static
discharges is provided

STATIC-SENSITIVE COMPONENTS

The following precautions are applicable when per­
forming any maintenance involving internal access
to the instrument.
CAUTION
Static discharge can damage any semicon­
ductor 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 fol­
lowing precautions to avoid component damage:
1. Minimize handling
components.
2. Transport and store static-sensitive components
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
q u a l i f i e d s e r v i c e p e r s o n n e l .

MAINTENANCE

maintenance, trouble­
in " Static-Sensitive
of static-sensitive
Section 6—2246 1Y and 2246 Mod A Service
Com ponents." Routine cleaning instructions and
visual inspection checking for defects are covered in
" Preventive Maintenance." Internal testing capa­
bilities and diagnostic test routines are included in
the " Troubleshooting" part of this section. Circuit
board removal procedures are included in the
" Corrective Maintenance" part of this section.
Table 6-1
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
JFET
Linear microcircuits
Low-power Schottky TTL
TTL
(Least Sensitive)
aV o lta g e e q u iv a le n t fo r le ve ls (v o lta g e d isc h a rg e d
fro m a 100-pF c a p a c ito r th r o u g h a re s is ta n c e of
100
£ ) :
1
1 = 100 to 500 V
2 = 200 to 500 V
3 = 250 V
4 = 500 V
5 = 400 to 600 V
Relative
Susceptibility
Levels a
1
2
3
4
5
6
7
8
9
6 = 600 to 800 V
7 = 400 to 1000 V (est)
8 = 900 V
9 = 1200 V
6-1