Tektronix 7T11A, Instruction Manual

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Maintenance — 7T11A
2. Transport and store static-sensitive components or
assemblies in their original containers on a metal rail or con­
ductive foam. Label any package that contains
static-sensitive assemblies or components.
3. Discharge the static voltage from your body by wear­
ing a wrist strap while handling these components. Servic­
ing static-sensitive assemblies or components should be
performed only at a static free work station by qualified ser­
vice personnel. We recommend use of the Static Control
Mat, Tektronix Part No. 006-3414-00, and Wrist Strap,
Tektronix Part No. 006-3415-00.
Resistor Color Code
In addition to composition resistors, some metal-film re­
sistors are used in the 7T11A. The resistance values of
composition resistors and metal-film resistors are color
coded on the components with EIA color code (some
metal-film resistors may have the value printed on the body).
The color code is read starting with the stripe nearest the
end of the resistor. Composition resistors have four stripes
that consist of two significant figures, a multiplier and a tol­
erance value (see Figure 4-1 ). Metal-film resistors have five
stripes consisting of three significant figures, a multiplier and
a tolerance value.
4. Allow nothing capable of generating or holing a static
charge on the work station surface.
5. Keep the component leads shorted together when­
ever 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 covering capable of generating a static
charge.
9. Use a soldering iron that is connected to earth
ground.
10. Use only special antistatic suction-type desoldering
tools.
Capacitor Marking
The capacitance values of common disc capactitors and
small electrolytics are marked in microfarads on the side of
the component body. The white ceramic capacitors used in
the 7T11A are color coded in picofarads using a modified
EIA code (see Figure 4-1).
Diodes
The cathode end of each glass-encased diode is indi­
cated by a stripe, a series of stripes, or a dot. The cathode
and anode ends of metal-encased diodes can be identified
by the diode symbol marked on the body.
Semiconductor Lead Configuration
Figure 4-2 shows the lead configuration for semiconduc­
tor
devices used in this instrument.
Wiring Color Code
All insultated wire and cable used in the 7T11A is color
coded to facilitate circuit tracing. Table 4-2 gives the wiring
color code used in the 7T11A.
TABLE 4-2
Power Supply Wire Color Code
Supply
Color Code
+ 50 V
Orange/Red
+ 15 V Brown/Red
+5 V Black/Red
-15 V Black/Violet
-50 V Brown/Violet
Multi-Pin Connector Identification
Multi-pin connectors mate with groups of pins soldered
to circuit boards. Pin number 1 is indexed with a triangular
mark etched on the circuit board and molded on the holder
of the multi-pin connector, as shown in Figure 4-3. Each
group of pins is identified by its corresponding P number
etched on the circuit board. The J and P numbers on the
circuit boards correlate to the J and P circuit numbers on
schematic diagrams.
Interface Connector Pin Locations
The Interface circuit board couples the plug-in unit to the
associated oscilloscope mainframe. Figure 4-4 identifies the
pins on the Interface connector as shown in Section 8 on
Diagram 10.
4-3