it
around
in
hot
soapy water
and
rinse
it
in
clear
water. Then
dry
it thoroughly and
coat
it with
new
adhesive. When
new,
the
filter
is
coated
with "Filter
Coat"
,
a
product
of
the
Research Products
Corporation.
"
Filter
Coat"
should
be easy
to
get
locally; look
in
the classified
section
of
your
telephone
book
for
RP
Air
Filters,
or
EZ
Kleen
Air
Filters.
Other adhesive
materials
are
no
doubt
satis
factory.
Fan
Motor
The
fan
motor
bearings
will
require
oiling
every
few months or
every
thousand
hours
of
operation.
Use
a
good grade
of
light
machine
oil
and
apply
only
a
drop
or
two.
GENERAL
INFORMATION
Color
Coding
We
use
color
coded
wires
in
the
instruments
to
help
identify
the
various
circuits.
These
wires
will
be
either
a
solid
color
or
will
be
a
solid
color (including
black
and
white)
with
one or
more
colored
stripes.
The
colored
stripes
are
"
read"
in
the
same
manner
as
the
RETMA resistor
color
code. In
the
case
of
multiple
stripes
the
wide
stripe is
read
first.
Wires
carrying
positive
regulated-power
supply
voltages
are
white
and
the
stripes
indicate the
supply voltage.
For
example,
the
+
225-volt
supply
bus
will
be
coded
red-red-
brown
(2-2-1)
giving
two significant
figures
and the
decimal
multiplier.
The
negative-supply
bus
wires
are
black
and
the
stripes indicate
the
supply voltage.
For
example,
our
most
common
negative
supply
voltage
is
-150
v
and
is
carried
by
a
black
wire
coded
brown-green-brown
(1-5-1).
The
mains-voltage
leads
to the
power
trans
former
are
yellow
and
coded
brown-brown-
brown
(1-1-1).
The
tube
heater
leads
are
white
and
coded
6-1,
6-2,
6-3, etc.,
not
to
indicate
that
the
voltages
are different but
to
differentiate
between
circuits.
In
other
respects
the
color
coding
will
vary
from
instrument
to
instrument.
In general
all
signal-carrying
leads
are white
and
coded
with
a
single
colored
stripe.
In
a
few
places
where
the
number
of
leads
exceeded
the
capabilities
of
single-stripe
coding
we
have
used solid-color
leads.
Soldering
and
Ceramic
Strips
Many
of
the
components
in
your
Tektronix
instrument
are
mounted
on
ceramic
terminal
strips.
The
notches
in
these
strips are
lined
with
a
silver
alloy.
Repeated
use
of
excessive
heat,
or
use
of
ordinary
tin-lead
solder
will
break
down
the silver-to-ceramic
bond.
Occa
sional use
of
tin-lead solder
will
not
break
the
bond
if
excessive
heat
is
not
applied.
If
you
are
responsible
for
the
maintenance
of
a
large
number
of
Tektronix
instruments,
or
if
you
contemplate
frequent
parts
changes,
we
recommend
that
you
keep
on
hand
a
stock
of
solder
containing
about
3% silver.
This
type
of
solder
is
used
frequently
in
printed
circuitry
and should
be
readily
available
from
radio-supply
houses.
If
you
prefer, you can
order
the
solder
directly from
Tektronix
in
one-pound rolls.
Order
by Tektronix
part
number
251-514.
Fig.
4-1.
Soldering
iron
tip
properly
shaped
and
tinned.
Because
of
the
shape
of
the
terminals
on
the
ceramic
strips
it
is advisable
to
use
a
wedge-shaped
tip
on
your
soldering
iron
when
you are
installing
or
removing
parts
from
the
strips.
Fig.
4-1
will
show
you
the correct
shape
for
the
tip
of
the
soldering
iron.
Be
sure
and
file smooth all
surfaces
of
the
iron
4-2
Maintenance
- Type
515/515A
AA