Troubleshooting Equipment; Troubleshooting Techniques; Semiconductor Lead Configurations - Tektronix 2215A Instruction Manual

Maintenance— 2215A Service
gram in which each component can be found. These compo­
nent-locator tables are especially useful when more than
one schematic diagram is associated with a particular circuit
board.
Troubleshooting Charts
The troubleshooting charts contained in the "Diagrams"
section are to be used as an aid in locating malfunctioning
circuitry. To use the charts, begin with the Troubleshooting
Guide. This chart will help identify a particular problem area
for further troubleshooting.
Note that some troubleshooting-procedure boxes on
each chart contain numbers along their lower edges. These
numbers identify the applicable schematic diagram(s) to be
used when performing the action specified in the box.
Both General and Specific notes may be called out in the
troubleshooting-chart boxes. These notes are located on
the inner panels of the foldout pages. Specific Notes contain
procedures or additional information to be used in perform­
ing the particular troubleshooting step called for in that box.
General Notes contain information that pertains to the over­
all troubleshooting procedure.
Some malfunctions, especially those involving multiple
simultaneous failures, may require more elaborate trouble­
shooting approaches with references to circuit descriptions
in the "Theory or Operation" section of this manual.
Component Color Coding
Information regarding color codes and markings of resis­
tors and capacitors is located in the color-coding illustration
(Figure 9-1) at the beginning of the " Diagrams" section.
RESISTOR COLOR CODE. Resistors used in this instru­
ment are carbon-film, composition, or precision metal-film
types. They are color coded with the EIA color code; how­
ever, some metal-film resistors may have the value printed
on the body. The color code is interpreted by starting with
the strip that is nearest to one end of the resistor. Compo­
sition resistors have four stripes; these represent two sig­
nificant figures, a multiplier, and a tolerance value.
Metal-film resistors have five stripes which represent three
significant figures, a multiplier, and a tolerance value.
CAPACITOR MARKINGS. Capacitance values of com­
mon disc capacitors and small electrolytics are marked on
the side of the capacitor body. White ceramic capacitors are
color code in picofarads, using a modified EIA code.
6-6
Dipped tantalum capacitors
microfarads. The color dot indicates both the positive lead
and the voltage rating. Since these capacitors are easily
destroyed by reversed or excessive voltage, be careful to
observe the polarity and voltage rating.
DIODE COLOR CODE. The cathode end of each glass-
encased diode is indicated by either a stripe, a series of
stripes, or a dot. For most silicon or germanium diodes
marked with a series of stripes, the color combination of the
stripes identifies three digits of the Tektronix Part Number,
using the resistor color-code system (e.g., a diode having
either a pink or a blue strip at the cathode end, then a
brown-gray-green stripe combination, indicates Tektronix
Part Number 152-0185-00). The cathode and anode ends of
a metal-encased diode can be identified by the diode symbol
marked on its body.

Semiconductor Lead Configurations

Figure 9-2 in the "Diagrams" section shows the lead con­
figurations for semiconductor devices used in the instru­
ment. These lead configurations and case styles are typical
of those available at completion of the design of the instru­
ment. Vendor changes and performance improvement
changes may result in changes of case styles or lead con­
figurations. If the device in question does not appear to
match the configuration in Figure 9-2, examine the associ­
ated circuitry or consult a semiconductor manufacturer's
data sheet.
Multipin Connectors
Multipin connector orientation is indicated by two trian­
gles; one on the holder and one on the circuit board. Slot
numbers are usually molded into the holder. When a con­
nection is made to circuit-board pins, ensure that the trian­
gle on the holder and the triangle on the circuit board are
aligned with each other (see Figure 6-1).

TROUBLESHOOTING EQUIPMENT

The equipment listed in Table 4-1, or equivalent equip­
ment, may be useful when troubleshooting this instrument.

TROUBLESHOOTING TECHNIQUES

The following procedure is arranged in an order that en­
ables checking simple trouble possibilities before requiring
more extensive troubleshooting. The first four checks en­
sure proper control settings, connections, operation, and
adjustment. If the trouble is not located by these checks, the
remaining steps will aid in locating the defective component.
are color coded in