Fluke 341A - Page 31

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
A
343
A
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