Troubleshooting Aids; Troubleshooting Equipment - Tektronix 7B92 Instruction Manual

Maintenance-7B92 Servi ce
Troubl eshooting Aids
Diagrams. Circuit d iagrams are given on fo ldo ut pages in
Section 6. T he component number and electrical value of
each component in th is instrument is shQlNn on the
diagrams.
Ci rcui t Boards. Fig. 6-2 (located in the diagrams
section) shows the location of the circu it boards with in this
instrument along with the assembly numbers. T he assembly
numbers are used on t he diagrams to aid in locating the
boards. Pictures of t he circuit boards are shQlNn in the
Diagrams section, on t he back of the page opposite the
circuit diagram, to aid in crosHeferencing between the
diagrams and the ci rcuit-board pictures. Each electrical
component o.)n t he boards is identified by its circuit
number, as wel l as the interconnect ing wire or connectors.
The d iagrams are outlined with a blue line to show w h ich
portions of the circuit are located on a circuit board.
Switch Cam Identification . Switch cam numbers shown
on t he diagrams indicate t he position of t he cam in the
complete switch assembl y. The switch cams are numbered
from fron t to rear.
Di ode Color Code. T he cathode end of each glass
encased d iode is identified by a stripe, a series of stripes, or
a dot. For most si licon or germanium diodes with a series of
stripes, t he color code also indicates t he type of diode or
identifies the Tektronix Part Number using t he resistor
color-code system (e.g., a diode color coded blue-or
pink-brown·gray.green indicates Tektron ix Part Number
152·0185·00). The cathode and anode ends of a metal
encased d iode can be identified by t he diode symbol
marked on the body.
Wiring Color Code and Multi-Connector Identi -
fi ca tion . Insulated wire and cable used in the 7892 is color
coded to aid circuit tracing. Multi ·connector ho lders are
keyed with twO triangles (or a triangle and a dot ), one on
the connector holder and one on the circu it board. The
triangle on the multi-connector holder must match w ith t he
triangle on t he circuit board for normal circuit operation.
In special cases where multi-connect or holders are used as a
switch, the triangles may not match (see Operating Instruc·
tions for special multi·connector holder functions). The
color of the multi ·connector holder corresponds to the last
numeral of t he circuil number, using the EIA color code
(e.g., P22 is red) .
Interface Connect or Pin l ocations. The Interface circuit
board couples the 7892 to the associated oscil loscope . Fig.
3· 1 illustrates the locations of pins on the interface
connector as shown on the Voltage Distribution and
Output Connectors schematic in the diagrams section .
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Troubleshooting Equipment
The following equipment is useful for troubleshooting
the 7892.
1. T ransistor Tester
Descr ipt ion: Tektronix T ype 577 T ransistor·Curve
T racer or a 7CTl N Curve Tracer plug·in unit and a
7000-$eries Oscilloscope system .
Purpose: To test semiconductors used in this instru ·
ment.
2 . Volt·ohmmeter
Description : 20,000 ohms/volt. 0·500 volts DC.
A ccurate within 3%
Purpose : To measure voltages and resistance.
3. T est Oscilloscope
Description : DC to 100 megahertz frequency response,
five millivo lts to f ive volts/division. Use a 10X probe.
Purpose: To check the waveforms in the instrument.
4. Plug·l n Extender
Description: Rigid pl ug·in extender, T ektron ix Part
Number 067 ·0589·00.
Purpose: Permits operation of the 7892 outside the
plug·in compartment of the oscilloscope for better
access during troubleshooting .
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Fig. 3· 1. l oca1ion 0 1 pin s on In1erlaee eo nnect o r.
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