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Lexan
switch
shafts
and
spacers,
because they
will
react
with
the
Lexan. Also,
do
not
saturate
the switch
contacts,
which
have
been perma-
nently
lubricated.
c.
Printed
circuit
boards have
been coated with
epocast
(a
polyurethane
resin)
to inhibit
fungus
growth and
moisture
absorption.
When
soldering to a printed
circuit
land,
the
heat
from
the soldering iron
decom-
poses the epocast
resin,
leaving
a
charred
residue.
Upon
completion of
soldering,
this
residue
should be
removed
with
a solvent,
such
as toluol.
CAUTION!
The
following precautions
should be adhered
to
when
using
toluol:
Avoid
inhaling the vapors,
avoid
excessive
contact with the
skin,
and
keep
away
from open
flames.
Ensure
that
plastic
components
do not
come
into
contact with
toluol,
since
it
will
dissolve
most
types of
plastic.
d.
After
removal of
the
epocast
residue,
the affected
area
should be
recoated
with
a sealant.
A
spray can
of
Circuit
Coat (Furane
Plastic
Inc.,
4516
Brazil
Street,
Los
Angeles, California or
16
Spielman Road,
Fairfield,
New
Jersey)
may
be used
for recoating.
4-18.
115/230
VOLT CONVERSION
4-19.
The Model
341
A/343
A
may
be operated
from
either a
115
or
230
volt
ac
power
line,
depending
upon
the
connection of
the
power
transformer
primary
winding.
Convert
the
instrument
from one
type of
power
line
operation
to
the
other
by
the
following
procedure:
341
343
a.
Disconnect
the instrument
from
the
power
line.
b.
Remove
the
top
cover.
The power
transformer
is
located
in the rear
of
the instrument, near the
point
of
line
cord
entry.
c.
Orient the
instrument
and perform
the appropriate
electrical
connections
as
shown
in
Figure
4-4.
d.
Use
the
proper
fuse
for
the
selected voltage,
as
specified in
paragraph
4-20.
4-20.
FUSE
REPLACEMENT
4-21.
Instrument
fuses are
contained
in
bayonet
type
fuse
holders located
at
the
rear
of the instrument. Correct
values for the fuses are
as
follows:
REFERENCE
DESIGNATION
FUNCTION
RATING
FI
Line
fuse
1
1
5
volt
connections
1
amp,
slow-blow
230
volt
connections
1/2
amp,
slow-blow
F2
High
voltage
1/16
amp,
slow-blow
fuse
4-22.
LAMP REPLACEMENT
4-23.
RANGE,
LIMIT ON,
and
power
ON
lamps
are
lo-
cated
immediately behind
the
front panel.
They
are
accessible
from
the
top of
the
instrument
after
removing
the
top instrument cover
and
the
narrow
front
cover
just
Figure
4-4.
115/230
VOLT CONVERSION
4-5
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