Eberline E-520 - SECTION IV MAINTENANCE; A. DISASSEMBLY AND REASSEMBLY; B. PREVENTIVE MAINTENANCE; C. CALIBRATION

MODEL E-520
SECTION IV
MAINTENANCE
A.
DISASSEMBLY
AND
REASSEMBLY
]. BATTERIES
The
batteries
are
secured
in
capitive
holders
on
the
etched
board.
The
holding
straps
may
be
removed
by
hand,
but
a
small
screwdriver
facilitates
removal.
Pull
the
batteries
from
the
holders.
Replace
by
sliding
batteries
into
holders,
making
certain
they
are
centered
and
of
the
correct
polarity.
Replace
holding
straps.
2. ETCHED BOARD
The
etched
board
and
cover
may
be
separated
for
troubleshooting.
Proceed
as
follows:
a.
Remove
batteries
to
prevent
electrical
damage
during
disassembly.
b.
Remove
knob
and
mounting
nut
from
scale
switch.
c.
Remove
2
screws
that
secure
meter
to
circuit
board.
d.
Separate
board
and
cover
without
putting
undue
stress
on
wires.
e.
For
troubleshooting,
place
jumpers
from
meter
studs
to
corresponding
points
on
board
and
replace
batteries.
f.
Reassemble
in
reverse
order
of
disassembly.
B. PREVENTIVE MAINTENANCE
1.
Keep
the
instrument
clean
and
dry.
2.
Replace
batteries
when
their
check
reading
is
below
the
acceptable
level.
ORIGINAL
3. Remove batteries if the instrument is to be inactive
for a long period.
C. CALIBRATION
For maximum accuracy, the instrument should be cali-
brated under the same conditions as it will be used. Refer
to section IB, 2 g and 5 b for effects of battery voltage and
temperature.
The instrument can be calibrated to either counts
per minute or mR/hr on all ranges except the X100 (inter-
nal tube) range which must be calibrated to mR/hr only.
l.
Place
the
detector
in
a
gamma
radiation
field
equal
to
about
3/4
scale
on
the
meter.
2. Adjust the calibration control for the range
selected
until
meter
reading
agrees
with
radiation
field.
3.
Repeat
for
each
scale
(X.01,
X0.1,
X1.0
and
X100).
To
calibrate
to
counts
per
minute,
proceed
as
follows:
1.
Capacitively
couple
a
pulse
generator
into
the
detector
connector
using
a
capacitor
with
a
1
KV
or
higher
voltage
rating.
The
pulse
generator
must
have
a
negative
pulse
greater
than
15
mV
amplitude
and
a
frequency
range
covering
the
instrument
range.
2.
Adjust
pulse
generator
frequency
to
correspond
with
approximately
3/4
scale
meter
reading
and
adjust
the
cali-
bration
control
for
the
range
selected
until
meter
reading
agrees
with
the
frequency.
3.
Repeat
for
all
ranges
except
X100
(internal
tube).