Eddystone 990R - Re-alignment

Drive
cord
replacement
.
In
the
unlikely
event
of the
pointer
drive cord
breaking,
replacement
can
easily
be
effected
by
following
the instructions
given
below'.
A
new
cord
can
be
obtained
from
Eddystone
Radio
Ltd. by
quoting
the Part
No. D3631.
The
cord
supplied
is
of
the
exact
length
required
and
is
complete
with
end
termination.
NB s
Left-hand
and
right-hand in the
instructions
which
follow
apply
when
the
receiver
is
viewed from the
rear.
1.
Remove the
faulty
drive cord.
2.
Set
CAL
RE-SET ADJUSTER
to mid-
travel
position.
3.
Rotate
TUNING
CONTROL
to
full extreme
of anti-clockwise
rotation.
4.
Take
the knotted
end
of
the
replacement
cord
and
slide
this
into
the
slot
on
the
left-hand
drive
pulley
so
that the
knot
is
trapped
against
the
inner
wall.
5*
Pass the
free end
of the
cord under the
sprung
jockey
pulley,
up
and
over
the
left-
hand
guide pulley
and then
across the
scale
plate
towards
the
right-hand
guide
pulley.
Do not
attach
to
cursor at
this
stage.
6.
Hold the
cord
in
tension and
rotate the TUNING
CONTROL
to the
full
extreme
of
its
clockwise
rotation
so
that
five
complete
turns
of
cord
are
wound
onto
the
left-hand
drive
pulley.
7
.
Maintain
tension
to
prevent
cord
slipping and
then
pass the
free
end
over
the
right
hand
guide pulley,
down
and
under the
cursor
shift
pulley
and
then
across
towards
the
right-hand
drive
pulley.
8.
Attach
the
cord
to the
right-hand
drive
pulley
by
sliding
into
slot
so that
the
eyelet
is
trapped
against
the
inner
wall.
9.
Lift the
lower
run of
cord
so that
it
lies
over
the
two
inner
guide
pulleys
whioh
prevent
it fouling
the
controls
below.
10. Check
drive for
free
running by
rotating
TUNING
CONTROL
to
full
extreme
of
anti-
clockwise rotation.
11. Leave
control at
this
setting,
slide
cursor
to
"0"
on
logging
scale
and
attach
to
cord by
means
of
three hooks
on
rear
of
carrier.
12. Check
cursor
for
free
running
and
CAL
RE-SET
ADJUSTER
for
normal
operation.
Verify
scale
accuracy
by
checking
against
the
built-in
crystal
calibrator.
^-ALIGNMENT
General
.
Initial
factory alignment
of
the
receiver
will
hold
good
for
a
long
period
of time
and
re-alignment should
only
be
attempted
if
there
is
a clear
indication
that
such
adjustment
is in
fact
required.
Adjustments
should
be
made
only by
experienced
tech-
nicians
with
a
sound
knowledge of
the
procedures
involved
and
an
adequate
range
of
reliable
test
equipment must
be
available
if the
task
is
to
be
completed
correctly.
Comprehensive
instructions
covering all
phases
of
the
alignment
procedure
are given
here
for
the sake
of completeness but
in
most
cases
it
will
only
be
found
necessary
to
make minor
adjustments
to
compensate for
normal
component
ageing
or
replacement.
The
relevant
instructions can
be extracted
as
required.
All
dust
cores
are
self-locking
(rubber
string
and
silicone
core-retaining com-
pound)
so
that there is no need
to use wax etc.
after
adjustment.
Trimming capacitors
likewise
are
also
self-locking.
-
26
-