Soldering Techniques; Component Replacement - Tektronix 7B70 Time Base Instruction Manual

Maintenance-7670 (SN 6205000 and Up)
parts are manufactured or selected by Tektronix, Inc. to Metal Terminals. When soldering metal terminals (e.g.,
meet specific performance requirements, or are manufac- switch terminals, potentiometers, etc.), use 60-40 tin'-lead
tured for Tektronix, Inc. in accordance with our specifica- solder and a 15 to 50 watt soldering iron. Observe the
tions. These special parts are indicated in the parts list by following precautions when soldering metal terminals:
an asterisk preceding the part number. Most of the mechan-
ical parts used in this instrument have been manufactured
1. Apply only enough heat to make the solder flow
by Tektronix, Inc. Order all special parts directly from your
freely.
local Tektronix Field Office or representative.
2. Apply or~ly enough solder to form a solid connection.
Excess solder may impair the function of the part.
Ordering Parts. 'When ordering replacement parts from
Tektronix, Inc., include the following information:
3. If a wire extends beyond the solder joint, clip off the
excess.
1. lnstrument Type.
2. lnstrument Serial Number.
3. A description of the part (if electrical, include circuit
number).
4. Tektronix Part Number.
Soldering Techniques
- 1
Disconnect the instrument from the power source
before 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. Clean the flux from the solder joint with a flux-
-removing solvent.
Component Replacement
piiFl
Disconnect the equipment from the power source
before replacing components.
Relay Replacement. The relays in the 7B70 are manu-
factured by Tektronix Inc. I f a relay fails, a replacement
may be ordered from your local Tektronix Field Office or
representative. The five pin relay sockets on the circuit
board will accept only the five pin SPDT relay. It i s
possible, however, to place a five pin SPDT relay in an eight
pin socket intended for use with one of the eight pin relays.
This would not damage the instrument or the relay, but
would cause a malfunction of the instrument. The eight pin
DPDT relays may be placed in their sockets facing either
direction, as these relays are symmetrical.
C A U T I O N
m
The relays used in this instrument can be damaged by
heat. Do not apply a soldering iron to the relay
socket until the relay has been removed from the
socket.
Transistor Replacement. Transistors should not be re-
4.
Avoid excessive heating of the junction with the
cir-
placed unless actually defective. If removed from their
cuit board, as this could
separate
the circuit board wiring
sockets during routine maintenance, return them to their
from the laminate. original sockets. Unnecessary replacement of transistors
may effect the calibration of this instrument. When transis-
tors are replaced, check the operation of that part of the
5. Use electronic grade 60-40 tin-lead solder.
instrument which may be affected.
6. Clip off any excess lead length extending beyond the
Replacement transistors should be of the original type or
circuit board and clean off any residual flux with a flux-
a direct replacement. Remount the transistors in the same
removing solvent. Be careful that the solvent does not re-
manner as the original. Fig. 4-3 shows the lead configura-
move any printing from the circuit board. tions of the transistors used in this instrument. This view is
Scans by ArtekMedia O 2006