Soldering Techniques; Component Replacement - Tektronix 7B51 Instruction Manual

Special Parts. In addition to the standard electronic
components, some special parts are used in the Type 7B51.
These parts are manufactured or selected by Tektronix, Inc.
to meet specific performance requirements, or are manu-
factured for Tektronix, Inc. in accordance with our specifi-
cations. These special parts are indicated in the parts list by
an asterisk preceding the part number. Most of the
mechanical parts used in this instrument have been manu-
factured by Tektronix, Inc. Order all special parts directly
from your local Tektronix Field Office or representative.
Ordering Parts. When ordering replacement parts from
Tektronix, Inc., include the following information:
1. Instrument Type.
2. Instrument Serial Number.
3. A description of the part (if electrical, include circuit
number).
4. Tektronix Part Number.
Soldering Techniques
WARNING
Disconnect the instrument from the power source be-
fore soldering.
Circuit Boards. The components mounted on the circuit
boards in the amplifier can be replaced using normal circuit
board soldering techniques. Keep the following points in
mind when soldering on the circuit boards.
1. Use a pencil-type soldering iron with a power rating
from 15 to 50 watts.
2. Apply heat from the soldering iron to the junction
between the component and the circuit board.
3. Heat-shunt the lead of the component by means of a
pair of long-nosed pliers.
4. Avoid excessive heating of the junction with the cir-
cuit board, as this could separate the circuit board wiring
from the laminate.
5. Use electronic grade 60-40 tin-lead solder.
®
Maintenance-Type 7B51
6. Clip off any excess lead length extending beyond the
circuit board and clean off any residual flux with a flux-
removing solvent. Be careful that the solvent does not re-
move any printing from the circuit board.
Metal Terminals. When soldering metal terminals (e.g.,
switch terminals, potentiometers, etc.), use 60-40 tin-lead
solder and a 15 to 50 watt soldering iron. Observe the
following precautions when soldering metal terminals:
1. Apply only enough heat to make the solder flow
freely.
2. Apply only enough solder to form a solid connection.
Excess solder may impair the function of the part.
3. If a wire extends beyond the solder joint, clip off the
excess.
4. Clean the flux from the solder joint with a flux-
removing solvent.
Component Replacement
WARNING
Disconnect the equipment from the power source be-
fore replacing components.
Relay Replacement. The relay in. the Type 7B51 is
manufactured by Tektronix, Inc. If the relay fails, a re-
placement may be ordered from your local Tektronix Field
Office or representative. The eight-pin DPDT relay may be
replaced in its socket facing either direction, as this relay is
symmetrical.
Transistor Replacement. Transistors should not be re-
placed unless actually defective. If removed from their
sockets during routine maintenance, return them to their
original sockets. Unnecessary replacement of transistors
may effect the calibration of this instrument. When tran-
sistors are replaced, check the operation of that part of the
instrument which may be affected.
Replacement transistors should be of the original type or
a direct replacement. Remount the transistors in the same
manner as the origintal. Fig. 4-3 shows the lead configura-
tions of the transistors used in this instrument. This view is
as seen from the bottom of the transistor. When replacing
transistors, check the manufacturer's basing diagram for
correct basing.
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