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wheels
by reversing
the
proce-
dure used to
remove the old
one. BE SURE
the
fingers
of
the new
stylus
are
pointed
UP.
6. Close the front of
the case.
Latch both
catches at the
top
of the unit.
MAINTENANCE
NOTE: The
stylus may
be
damaged
if it is in front of the
pla-
ten when the
platen assembly
is
pulled
down.
Always
move the
stylus
to the
back side of the
pla-
ten
when
changing
the
paper
rolls.
Remember to move the belt
down to remove the
stylus.
Black carbon dust is created dur-
ing
the
recording process.
Use a
soft,
oil-free
rag
to clean the
viewing
door and metal
platen
be-
hind the
paper.
Low
pressure
compressed
air
may
be used to
blow
dust out of the case and
away
from
moving parts
if the air
is
dry
and free of oil.
All mechanical
connections
should be
checked
periodically
to
be sure
they
haven't worked
loose.
HIGH VOLTAGE is
present
in the
transmitter section when the
unit
is ON.
No
attempt
should
be
made
by any
unauthorized
per-
son to
modify
or
repair
the
elec-
tronic
section.
All electrical
connections
should
be checked
periodically
and
cleaned as
necessary.
The
face of the
transducer,
if
mounted
on the transom
should
be
washed
periodically
with mild
soapy
water to remove
any
ac-
cumulated rod
grime
or
oily
film.
This is
essential to have
good
contact between
the transducer
16
and the water.
DO
SECTION
Do
carry
a
spare
fuse,
stylus belt,
and roll
of
paper.
Do use
the
empty
cardboard core
from the last
roll of
paper
on the
take-up post.
Do
keep
the recorded
graphs
for
future
reference.
Do clean
the
stylus belt, wheels,
and
the rubber roller after
every
five rolls
ofpaper.
DON'T
SECTION
DONT OPEN THE
CASE WHEN
THE UNIT IS
ON.
Don't
pull
the
platen
assembly
down when the
stylus
is at the
front.
Don't store
any objects
inside the
case or behind the
viewing
win-
dow.
(Except
for small
pieces
of
tape.)
Don't
forget
to
tape
the
paper
to
the
take-up
core.
Don't rotate the
stylus
belt
up.
Don't use
oily cloths,
strong
sol-
vents,
or abrasive cleansers.
TROUBLESHOOTING
SECTION
Symptom
On/Off switch is
'ON",
but the
stylus
and
paper
don't move.
What To Do
Check
fuse;
check connections at
battery
for
tightness
and
corrosion.
Symptom
On/Off
switch is
"ON",
have
zero
mark,
but no echoes or bottom
signal.
What To
Do
Be
sure the transducer is
plugged
—
GRAYL NI
/
-
rrIviv
Han
'nan
a n--• a.
r
Figure
4
When
high Sensitivity settings
are
used,
a second bottom echo
will
appear.
This is normal
and is
caused
by
the
returning
signal
re-
flecting
off the surface of
the
water,
making
a second
trip
to
the
bottom and back.
If detailed information about
brush
piles,
individual
fish,
or the
I
thermocline is
desired,
the
Sen-
sitivity
knob
should be rotated to
approximately
the ¾
point.
Refer
to the
illustration below to see
Figure
6
2
'1
SENSITIVITY:
TOO LOW
what effect the
Sensitivity
control
setting
has on
the recorded
information.
Recording
individual fish
with an
"arched"
signature
can
usually
be
accomplished
at
trolling speed
with the
Sensitivity
knob at the ¾
point,
or
higher.
Refer to the sec-
tion "Arched
Signatures"
for more
information about
this
important
function of
your
recorder.
Suppression
Control
The
Suppression
Control is
used to reduce
interference from
noise.
Noise,
in
electronic
terms,
is
any
undesired
signal.
It can
be
caused
by
an electrical
source,
(such
as the
engine's
ignition sys-
tem)
or
by
air bubbles
in disturbed
water which is call
cavitation. In
both
cases,
the noise
could
pro-
duce unwanted marks on
the
paper. (See Figures
7 &
8.)
Fortunately,
noise
pulses
are rela-
tively
short in time
compared
to
real sonar
signals. Advancing
the
Suppression
knob will cause
the
system
to
reject
these
unwanted,
short
pulses
without
reducing
the
5
Figure
5
SENSITIVITY: PROPER SETTiNG
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