length
of
wooden
dowel,
with
one
end
shaped
as
shown
in
Fig.
4-5.
In
soldering
to
terminal
pins
mounted
in
plastic
rods
it is
necessary
to
use
some
form
of
"
heat
sink"
to
avoid
melting
the
plastic.
A pair of
long-nosed
pliers
(see
Fig.
4-6)
makes
a
convenient
tool
for this
purpose.
Fig. 4-5.
A
soldering
aid
constructed
from
a
1/4
inch
wooden
dowel.
Ceramic
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.
4-7.
Fig.
4-6.
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.
To
replace
ceramic
strips
which
bolt
to
the
chassis,
screw
a
#2-56
nut
onto
each
mounting bolt,
positioning
the
nut
so
that
the distance between
the bottom
of
the nut
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
#2-56
starwasher
between
each
nut
and
the
chassis.
Place
a
second
set
of
#2-56
flatwashers
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.
Fig.
4-7.
Two
types
of
ceramic
strip
mountings.
Mounting
Later Ceramic Strips
To
replace
strips
which
mount
with
snap-in
plastic
fittings,
first
remove
the
original
fittings
from
the
chassis.
Assemble
the mounting
post
on
the
ceramic
strip.
Insert
the
nylon
collar
into
the
mounting
holes
in
the
chassis.
Care
fully
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.
4-4
Maintenance
-
Type
515/515A