Tektronix 535A, Инструкция по эксплуатации

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Maintenance — Type 535A
Fig. 5-6. A slight fillet of solder is formed around the wire when
heat is applied correctly.
SOLDERING IRON
LONG NOSED
PLIERS
PLASTIC COIL FORM
Fig. 5-7. Soldering to a terminal. Note the slight fillet of solder—
exaggerated for clarity—formed around the wire.
Fig. 5-8. Soldering to a terminal mounted in plastic. Note the
use
of
the long-nosed pliers between the iron and the coil form to
absorb the heat.
Ceramics Strips
Two distinct types of ceramic strips have been used in
Tektronix instruments. The earlier type mounted on the
chassis by means of #2-56 bolts and nuts. The later type
is mounted with snap-in, plastic fittings. Both styles are
shown in Fig. 5-9.
To replace ceramic strips which bolt to the chassis, screw
a #2-56 nut into each mounting bolt, positioning the bolt
so that the distance between the bottom of the bolt and
the bottom of the ceramic strip equals the height at which
you wish to mount the strip above the chassis. Secure the
nuts to the bolts with a drop of red glyptal. insert the
bolts through the holes in the chassis where the original
strip was mounted, placing a #2 starwasher between each
nut and the chassis. Place a second set of #2 starwashers
on the protruding ends of the bolts, and fasten them firmly
with another set #2-56 nuts. Place a drop of red glyptal
over each of the second set of nuts after fastening.
In soldering to metal terminals (for example, pins on a
tube socket) a slightly different technique should be em­
ployed. Prepare the iron as outlined above, but tin with
ordinary tin-lead solder. Apply the iron to the part to be
soldered. Use only enough heat to allow the solder to flow
freely along the wire so that a slight fillet will be formed.
When replacing wires in terminal slots clip the ends neat­
ly as close to the solder joint as possible. In clipping the
ends of wires take care the end removed does not fly across
the room as it is clipped.
Occassionally you will wish to hold a bare wire in place
as it is being soldered. A handy device for this purpose is
a short length of wooden dowel (see Fig. 5-10).
In soldering to terminal points mounted in plastic rods it is
necessary to use some form of “heat sink” to aviod melting
the plastic. A pair of long-nosed pliers makes a convenient
tool for this purpose.
Mounting Later Ceramic Strips
To replace strips which mount with snap-in plastic fit­
tings, first remove the original fittings from the chassis. As­
semble the mounting post on the ceramic strip. Insert the
nylon collar into the mounting holes in the chassis. Carefully
force the mounting post into the nylon collars. Snip off the
portion of the mounting post which protrudes below the nylon
collar on the reverse side of the chassis.
NOTE
Considerable force may be necessary to push the
mounting rods into the nylon collars. Be sure
that you apply this force to that area of the cer ­
amic strip directly above the mounting rods.
5-4