ORTEC 427 User manual
PRECISION
INSTRUMENTATION
FOR
RESEARCH
Oak
Ridge
Technical
Enterprises
Corporation
OAK
RIDGE,
TENNESSEE
INSTRUCTION
MANUAL
MODEL
427
DELAY
AMPLIFIER
Serial
No.
Purchaser.
1
INSTRUCTION
MANUAL
MODEL
427
DELAY
AMPLIFIER
Date
Issued
OAK
RIDGE
TECHNICAL
ENTERPRISES
CORPORATION
p.
O.
BOX
C
OAK
RIDGE,
TENNESSEE
Telephone
(615)
483-8451
TWX
810-572-1078
I
Oak
Ridga
Technical
Enterprises
Corporation
1966
Printed
in
U.S.A.
CONTENTS
WARRANTY
PHOTOGRAPH
1.
DESCRIPTION
2.
SPECIFICATIONS
2.1
Electrical
2.2
Mechanical
3.
INSTALLATION
3.1
General
Installation
Considerations
3.2
Connection
to
Power
-
Nuclear
Standard
Bin,
ORTEC
Model
401/402
3.3
Signal
Connections
to
Model
427
4.
OPERATING
INSTRUCTIONS
4.1
Initial
Testing
and
Observation
of
Pulse
Waveforms
4.2
Connector
Data
4.3
Typical
Operating
Considerations
5.
CIRCUIT
DESCRIPTION
6.
MAINTENANCE
6.1
Testing
Performance
of
the
Delay
Amplifier
6.2
Changing
Amplifier
Gain
6.3
Suggestions
for
Troubleshooting
6.4
Tabulated
Test
Point
Voltages
7.
Model
427
Block
Diagram
427-0100-Bl
Model
427
Schematic
427-0100-Sl
r
i
I
i
t
i
STANDARD
WARRANTY
FOR
ORTEC
ELECTRONIC
INSTRUMENTS
DAMAGE
IN
TRANSIT
Shipments
should
be
examined
immediately
upon
receipt
for
evidence
of
external
or
con
cealed
damage.
The
carrier
making
delivery
should
be
notified
immediately of
any
such
damage,
since
the
carrier
is
normally
liable
for
damage
in
shipment.
Packing
materials,
waybills,
and
other
such
documentation
should
be
preserved
in
order
to
establish
claims.
After
such
notification
to
the
carrier,
notify
ORTEC
of
the
circumstances
so
that
we
may
assist
in
damage
claims
and
in
providing
replacement
equipment
when
necessary.
WARRANTY
ORTEC
warrants
its
electronic
products
to
be
free
from
defects
in
workmanship
and
materials,
other
than
vacuum
tubes
and
semiconductors,
for
a
period
of
twelve
months
from
date
of
ship
ment,
provided
that
the
equipment
has
been
used
in
a
proper
manner
and
not
subjected
to
abuse.
Repairs
or
replacement,
at
ORTEC
option,
will
be
made
without
charge
at
the
ORTEC
factory.
Shipping
expense
will
be
to
the
account
of
the
customer
except
in
cases
of
defects
discovered
upon
initial
operation.
Warranties
of
vacuum
tubes
and
semiconductors,
as
made
by
their
manufacturers,
will
be
extended
to
our
customers
only
to
the
extent
of
the
manufacturers'
liability
to
ORTEC.
Specially
selected
vacuum
tubes
or
semiconductors
cannot
be
warranted.
ORTEC
reserves
the
right
to
modify
the
design
of
its
products
without
incurring
responsibility
for
modification
of
previously
manufactured
units.
Since
installation
conditions
are
beyond
our
control,
ORTEC
does
not
assume
any
risks
or
liabilities
associated
with
the
methods
of
installation,
or
installation
results.
QUALITY
CONTROL
Before
being
approved
for
shipment,
each
ORTEC
instrument
must
pass
a
stringent
set
of
quality
control
tests
designed
to
expose
any
flaws
in
materials
or
workmanship.
Permanent
records
of
these
tests
are
maintained
for
use
in
warranty
repair
and
as
a
source
of
statistical
information
for
design
improvements.
REPAIR
SERVICE
ORTEC
instruments
not
in
warranty
may
be
returned
to
the
factory
for
repairs
or
checkout
at
modest
expense
to
the
customer.
Standard
procedure
requires
that
returned
instruments
pass
the
same
quality
control
tests
as
those
used
for
new
production
instruments.
Please
contact
the
factory
for
instructions
before
shipping
equipment.
ORTEC
€>
MODEL
427
DELAY
AMPLIFIER
.25
fiiec
.5/Mec
D
E
L
A
Y
0
U
T
ti%ec
D
E
L
A
Y
I
N
/isec
:
Msec
INPUT
output
©
Model
427
Delay
Amplifier
NOTICE
Slide
switches
are
used
in
the
Model
427
to
select
the
desired
amount
of
signal
delay.
The
contacts
of
these
switches
are
coated
with
a
lubricant
to
prevent
them
from
oxidizing.
If
this
lubricant
is
removed
from
a
portion
of
the
contact
oxidation
may
occur.
This
can
result
in
some
difficulty
with
these
switches
making
contact
properly.
This
problem
can
be
alleviated
by
operating
the
switch
a
few
times.
If
a
switch
does
not
make
contact
either
the
signal
will
not
appear
at
the
output
or
it
will
appear
at
a
reduced
amplitude.
If
this
happens,
simply
operate
the
switch
a
few
times
to
remove
the
oxide.
427112966
1-1
MODEL
427
DELAY
AMPLIFIER
1.
DESCRIPTION
The
Model
427
Delay
Amplifier
has
a
nominal
gain
of
unify
and
provides
the
capability
of
linearly
delaying
a
linear
or
logic
signal
from
zero
to
4.75
microseconds
in
0.25
micro
second
increments.
The
amount
of
delay
is
selected
by
five
front
panel
switches.
This
delay
is
accomplished
by
inserting
any
combination
of
five
delay
lines
of
0.25,
0.5,
1.0,
1.0,
or
2.0
microseconds
in
series
with
the
signal
path.
These
delay
lines
are
terminated
in
their
characteristic
impedance
at
both
ends
to
minimize
impedance
mismatch
and
resul
tant
pulse
reflections
on
the
lines.
NOTE:
The
427
has
a
limited
bandwidth
as
shown
in
the
specifications.
Due
to
this
fact,
it
should
not
be
used
to
delay
signals
of varying
bandwidth
such
as
the
output
of
a
biased
amplifier
(i.e..
Model
408).
If
a
biased
amplifier
is
used
in
a
system,
the
427
should
be
used
in
front
of
it
or
after
the
411
Pulse
Stretcher
where
the
pulses
have
a
uniform
bandwidth.
427112966
2-1
2.
SPECIFICATIONS
2.1
Electrical
Input
Polarity
Input
Signal
Span
Input
Impedance
Gain
Gain
Variation
with
Delay
Feedthrough
and
Delay
Ripple
Linear
Delay
Minimum
(Zero)
Delay
Maximum
Delay
Delay
Line
Tolerances
Rise
Time
and
Bandwidth
as
a
Function
of
Delay
Output
Output
Impedance
Linearity
Either
positive
or
negative
±10
volts
linear
range
Greater
than
IK
Unity
+2%
at
zero
delay
+
10%,
-2%
for
any
combination
of
delays
(1
psec
DRC
shaped
pulse)
Less
than
2%
(Ipsec
RC
shaped
pulse)
Any
combination
of
the
following:
0.25,
0.5,
1.0, 1.0,
and
2.0psec
60
nsec
4.75psec
±5%
Delay
Rise
Time
(ns)
Bandwidth
0
280
1.25
MHz
0.25
280
1.25
MHz
0.5
290
1.20
MHz
1.0
310
1.13
MHz
2.0
340
1.03
MHz
3.0
360
972
KHz
4.0
370
945
KHz
4.5
380
920
KHz
4.75
400
875
KHz
Linear
range
0
to
±10
volts.
0
to
±11
volts
maximum
Approximately
1
ohm,
short-circuit
protected
Integral
nonlinearity
less
than
±0.08%
from
0.1
to
10
volts
2-2
Temperai-ure
Stability
Operating
Temperature
Range
Input
and
Output
Connectors
Power
Requirements
Gain
shift
of
the
amplifier
is
less
than
±0.01%
per
°C;
and
additional
shift
of
-0,013%
per°C
should
be
expected
for
each
microsecond
of
delay
used.
0
to
5CPC
BNC
—
UG-1094
A/U
and
UG-1094/U
+24V
+12V
-12V
-24V
25
mA
14
mA
3
mA
37
mA
2.2
Mechanical
The
Model
427
is
housed
in
a
single-width
Nuclear
Standard
Module
(refer
to
USAEC
Report
TID-20893),
and
weighs
two
pounds.
The
Model
427
does
not
contain
a
power
supply
and
therefore
must
obtain
the
necessary
operating
power
from
the
Nuclear
Standard
Bin
and
Power
Supply,
ORTEC
Model
401/402.
All
signals
in
and
out
of
the
module
are
on
front
panel
BNC
connectors
and
the
input
power
is
via
the
AMP
202515-3
connector
on
the
rear
panel.
3-1
3.
INSTALLATION
3.1
General
Installation
Considerations
The
Model
427,
used
in
conjunction
with
a
Model
401/402
Bin
and
Power
Supply,
is
intended
for
rack
mounting,
and
therefore
it
is
necessary
to
ensure
that
vacuum
tube
equipment
operating
in
the
same
rack
with
the
Model
427
have
sufficient
cooling
air
circulating
to
prevent
any
localized
heating
of
the
all-transistor
cir
cuitry
used
throughout
the
module.
The
temperature
of
equipment
mounted
in
racks
can
easily
exceed
the
recommended
maximum
unless
precautions
are
taken.
The
Model
427
should
not
be
subjected
to
temperatures
in
excess
of
120PF
{5(fC).
3.2
Connection
to
Power
-
Nuclear
Standard
Bin,
ORTEC
Model
401/402
The
Model
427
contains
no
internal
power
supply,
and
therefore
must
obtain
power
from
a
Nuclear
Standard
Bin
and
Power
Supply
such
as
the
ORTEC
Model
401/402.
It
is
recommended
that
the
bin
power
supply
be
turned
off
when
inserting
or
removing
modules.
The
ORTEC
400
Series
is
designed
so
that
it
is
not
possible
to
overload
the
bin
power
supply
with
a
full
complement
of
modules
in
the
bin;
however,
this
may
not
be
true
when
the
bin
contains
modules
other
than
those
of
ORTEC
design,
and
in
such
cases,
the
power
supply
voltages
should
be
checked
after
the
insertion
of
modules.
The
ORTEC
Model
401/402
has
test
points
on
the
power
supply
control
panel
to
monitor
the
dc
voltages.
When
using
the
Model
427
outside
the
Model
401/402
Bin
and
Power
Supply,
be
sure
that
the
jumper
cable
used
properly
accounts
for
the
power
supply
grounding
circuits
provided
in
the
recommended
AEC
standards
of
TID-20893.
Both
clean
and
dirty
ground
connections
are
provided
to
ensure
proper
reference
voltage
feedback
into
the
power
supply,
and
these
must
be
preserved
in
remote
coble
installations.
Care
must
also
be
exercised
to
avoid
ground
loops
when
the
module
is
not
physically
in
the
bin.
3.3
Signal
Connections
to
Model
427
The
Model
427
input
is
compatible
with
all
linear
output
signals
of
the
ORTEC
400
Series
of
modular
electronic
instruments.
The
medium-speed
logic
pulse
of
the
400
Series
is
also
suitable
for
use
with
the
Model
427;
however,
the
rise
time
of
the
logic
pulse
will
be
increased
considerably
because
of
the
limited
bandwidth
of
the
Model
427.
(See
specifications
for
bandwidth
and
rise
time
vs
delay.)
The
signal
range
of
the
input
is
from
0
to
10
volts.
The
input
pulse
shape
can
be
as
wide
as
the
typical
preamplifier
output,
i.e.,
a
time
constant
of
50
microseconds,
or
as
narrow
as
300
to
400
nanoseconds.
The
connecting
coaxial
cable
should
be
terminated
in
its
characteristic
impedance
at
the
input
connector
when
cable
lengths
exceed
approximately
10
feet
(see
Figure
1),
3-2
^ODEL
410
RG-62/U
OR
RG-
63/U
(J^GDEL
427
RG-62/U
OR
RG-63/U
ANALYZER
l>
R
S
:
2|N
too
a
BNC
TERMINATOR
ICQ
A
BNC
TERMINATOR
GATE
SIGNAL
FROM
COINGIDENOE
OF
CROSSOVER
DERIVED
Z|N
>
1000
O
FIG.
I.
BLOCK
DIAGRAM
OF
A
SYSTEM
USING
PROPER
CABLES
AND
TERMINATORS
The
input
impedance
of
the
Model
427
is
approximately
1100
ohms.
It
is
recom
mended
that
RG-62/U
or
RG-63/U
coaxial
cable
be
used
due
to
their
relatively
high
impedance
of
93
and
125
ohms,
respectively.
If
long
cables
having
impedances
less
than
93
ohms
must
be
used,
care
must
be
taken
to
ensure
that
the
driving
source
can
drive
and
terminate
the
cable.
For
example,
when
driving
from
an
ORTEC
linear
output
with
an
output
impedance
of
less
than
10
ohms,
a
50-ohm
series
resistor
should
be
used
between
the
driving
source
and
the
coaxial
cable
(see
Figure
2).
This
makes
the
output
impedance
of
the
ampli
fier
equal
to
the
characteristic
impedance
of
the
coaxial
cable;
therefore,
it
is
not
necessary
to
terminate
the
cable
at
the
input
of
the
Model
427.
However,
if
the
cable
is
terminated
at
the
input
connector,
the
signal
at
the
Model
427
input
will
be
one-half
the
output
signal
of
the
driving
source
due
to
the
series
resistor.
The
above
method
of
series
termination
is
recommended
for
ORTEC
linear
output
circuits
when
it
is
necessary
to
drive
a
50-ohm
load
at
high
count
rates.
This
modification
can
be
made
on
the
Model
427
by
removing
the
cover
plate
and
replacing
the
short-
piece
of
wire
between
R
and
S
on
the
circuit
board
with
a
50-ohm
resistor.
MODEL
410
RG-58/U
MODEL
427
\-rv
RG-5a/U
ANALYZER
Wv—
50
n
R
S
50
A
GATE
SIGNAL
FROM
COINCIDENCE
OF
CROSSOVER
DERIVED
PULSE
FIG.
2.
BLOCK
DIAGRAM
OF
A
SYSTEM
WHEN
LONG
50
A
CABLES
MUST
BE
USED
Linear
Output
Signal
Connections
and
Terminating
Impedance
Considerations
The
source
impedance
of
the
0-10
volt
standard
linear
outputs
of
most
400
Series
modules
is
approximately
1
ohm.
Interconnection
of
linear
signals
iS/
thus,
non-critical
since
the
input
impedance
of
circuits
to
be
driven
is
not
important
in
determining
the
actual
signal
span,
e.g.,
0-10
volts,
de
livered
to
the
following
circuit.
Paralleling
several
loads
on
a
single
out
put
is
therefore
permissible
while
preserving
the
0-10
volt
signal
span.
Short
lengths
of
interconnecting
coaxial
cable
(up
to
approximately
4
feet)
need
not
be
terminated.
However,
if
a
cable
longer
than
approximately
4
feet
is
necessary
on
a
linear
output,
it
should
be
terminated
in
a
resistive
load
equal
to
the
cable
impedance.
Since
the
output
impedance
is
not
purely
resistive,
and
is
slightly
different
for
each
individual
module,
when
a
certain
given
length
of
coaxial
cable
is
connected
and
is
not
terminated
in
the
characteristic
impedance
of
the
cable,
oscillations
will
generally
be
observed.
These
oscillations
can
be
suppressed
for
any
length
of
cable
by
properly
terminating
the
cable
either
in
series
at
the
sending
end
or
in
shunt
at
the
receiving
end
of
the
line.
To
properly
terminate
the
cable
at
the
receiving
end,
it
maybe
necessary
to
consider
the
input
impedance
of
the
driven
circuit,
choosing
an
additional
parallel
resistor
to
make
the
combination
produce
the
desired
termination
resistance.
Series
terminating
the
cable
at
the
sending
end
may
be
preferable
in
some
cases
where
re
ceiving
and
terminating
is
notdesirable
or
possible.
When
series
terminat
ing
at
the
sending
end,
full
signal
span,
i.e.,
amplitude,
isobtainedat
the
receiving
end
only
when
it
is
essentially
unloaded
or
loaded
with
an
impedance
many
times
that
of
the
cable.
This
may
be
accomplished
by
inserting
a
series
resistor
equal
to
the
characteristic
impedance
of
the
ca
ble
internally
in
the
module
between
the
actual
amplifier
output
on
the
etched
board
and
the
output
connector.
It
must
be
remembered
that
this
impedance
is
in
series
with
the
input
impedance
of
the
load
being
driven,
and
in
the
case
where
the
driven
load
is
900
ohms,
a
decrease
in
the
signal
span
of
approximately
10%
will
occur
for
a
93-ohm
transmission
line.
A
more
serious
loss
occurs
when
the
driven
load
is
93ohms
and
the
transmis
sion
system
is
93
ohms.
In
this
case,
a50%
loss
will
occur.
BNC
connec
tors
with
internal
terminators
are
available
from
a
number
of
connector
manufacturers
in
nominal
values
of
50,
100,
and
lOOOohms.
ORTEC
stocks
in
limited
quantity
both
the
50
and
100
ohm
BNC
terminators.
The
BNC
terminators
are
quite
convenient
to
use
in
conjunction
with
a
BNC
tee.
4-1
4.
OPERATING
INSTRUCTIONS
4.1
Initial
Testing
and
Observation
of
Pulse
Waveforms
Refer
to
Section
6.1
of
this
manual
for
information
concerning
testing
perfor
mance
and
observing
pulse
waveforms.
4.2
Connector
Data
CNl
-
INPUT
CNl
is
the
INPUT
BNC
connector
for
the
incoming
pulse
that
is
delayed,
i.e.,
temporarily
stored,
in
passing
through
the
amplifier.
The
input
impedance
is
approximately
1100
ohms,
dc
coupled
to
ground.
The
input
impedance
may
be
.
shunted
at
CNl
by
a
fixed
resistor
to
the
characteristic
impedance
of
the
coaxial
cable
feeding
the
connector.
If
the
input
is
shunted,
care
must
be
taken
to
ensure
that
the
driving
source
can
drive
the
terminated
cable;
this
is
particularly
a
problem
for
50-ohm
coaxial
cable.
The
input
voltage
rated
range
is
0
to
±10
volts.
The
voltage
gain
of
the
Model
427
is
nominally
unity.
CN2
-
OUTPUT
CN2
is
the
OUTPUT
BNC
connector.
The
output
driving
impedance
is
approximately
one
ohm
and
is
short-circuit
protected.
If
a
higher
output
impedance
is
desired
for
sending
end
termination
of
the
coaxial
cable,
see
Sections
3.3
and
5.3
of
this
manual
for
modification
instructions.
OUTPUT
TEST
POINT
There
is
an
oscilloscope
test
point
on
the
front
panel
for
monitoring
the
signal
on
the
OUTPUT
BNC
connector.
This
test
point
has
a
470-ohm
series
resistor
con
necting
it
to
the
OUTPUT
BNC
connector.
POWER
CONNECTOR
The
power
connector
is
a
nuclear
standard
power
connector,
AMP
202515-3.
4.3
Typical
Operating
Considerations
The
Model
427
is
typically
used
in
a
linear
system
after
the
main
pulse
shaping
amplifier.
It
is
also directly
compatible
with
and
can
be
driven
from
any
of
the
ORTEC
400
Series
linear
output
circuits.
The
input
and
output
signal
range
is
rated
from
0
to
10
volts,
positive
or
negative.
After
the
desired
amount
of
delay
has
been
selected,
the
Model
427
output
should
be
checked
with
on
oscilloscope
to
ensure
that
the
dynamic
range
of
the
unit
is
not
exceeded.
The
gain
of
the
Model
427
is
nominally
unity,
but
it
increases
to
approximately
1.1
when
all
of
the
delay
(4.75
microseconds)
is
selected.
5-1
5.
CIRCUIT
DESCRIPTION
The
circuit
of
the
Model
427
consists
of
three
basic
sections.
(See
Drawings
427-
0100-Bl
and
427-0100-S1.)
The
input
section
is
a
feedback
amplifier
loop,
Ql,
Q2,
and
Q3.
The
gain
of
this
loop
is
changed
to
compensate
for
the
delay
line
loss
by
changing
Ry.
The
second
section
includes
the
five
delay
lines
and
their
associated
switches.
The
last
section
is
the
output
cable
driver
loop,
composed
of
transistors
Q4
through
Q7.
5.1
The
input
section
is
a
basic
current
feedback
amplifier
composed
of
Ql
and
Q2
with
an
additional
emitter-follower,
Q3,
added
to
make
the
loop
linearly
pass
both
positive
and
negative
signals.
The
gain
of
this
loop
is:
R7
_
Rf
R2+R3+R37+R38+R39+R40+R41+R42
Ry
(See
Drawings
427-0100-Bl
and
427-0100-31.)
Each
time
a
delay
line
is
switched
into
the
circuit,
the
closed
loop
gain
is
increased
to
compensate
for
the
signal
loss
in
the
delay
line.
The
gain
of
this
loop
is
increased
by
reducing
Ry;
e.g.,
short
circuiting
R37
when
the
0.25-microsecond
delay
line
is
inserted
in
the
signal
path.
5.2
The
second
section
is
composed
of
the
five
delay
lines
and
their
associated
switches.
These
are
4PDT
switches.
The
first
pole
of
each
switch
is
used
to
increase
the
gain
of
the
first
amplifier
loop
to
compensate
for
the
signal
loss
in
the
delay
line.
The
second
pole
of
each
switch
is
grounded
to
prevent
signal
feedthrough
in
the
switch.
The
third
and
fourth
poles
are
used
to
connect
the
delay
lines
in
series
with
the
signal
path
or
remove
them
from
the
circuit.
All
or
any
combination
of
these
delay
lines
may
be
inserted
in
series
to
give
a
total
delay
of
4.75
microseconds.
Resistors
R11
and
R12
are
used
to
terminate
the
delay
lines
at
both
ends
to
minimize
impedance
mismatch
and
resultant
pulse
reflections
on
the
lines.
5.3
The
second
amplifier
loop
consists
of
a
cable
driver
with
the
addition
of
Q5
to
regulate
the
emitter
voltage
of
Q4.
The
output
driver
loop
consists
of
transistors
Q4,
Q6,
Q7,
and
Q8.
04
and
06
constitute
the
typical
npn-pnp
loop;
they
drive
quite
well
in
the
negative
direction
but
not
in
the
positive
direction.
The
addition
of
emitter-follower
07
in
this
loop
allows
the
overall
loop
to
handle
both
positive
and
negative
signals
quite
easily
to
plus
and
minus
11
volts
into
a
100-ohm
load,
but
an
accidental
short
circuit
of
the
output
will
cause
07
to
be
destroyed.
The
addition
of
08
serves
to
protect
07.
The
function
of
08
is
to
provide
a
method
of
limiting
the
average
current
through
07
to
a
value
less
than
that
required
to
destroy
07.
08
can
supply
large
peak
currents
from
the
col
lector
capacitors
C13
and
C14;
these
currents
can
flow
directly
through
08
and
07
and
thence
into
the
load.
5-2
In
the
event
of
a
short
circuit
on
the
output,
the
absolute
magnitude
of
current
that
can
be
supplied
through
Q7
and
Q8
from
C13
and
C14
is
less
than
that
re
quired
to
destroy
either
Q7
or
Q8.
Capacitors
C13
and
C14
charge
back
to
the
B+
voltage
through
R28
in
the
absence
of
any
input
pulse.
The
output
impedance
of
this
loop
is
approximately
one
ohm.
If
an
output
impe
dance
greater
than
one
ohm
is
desired,
the
short
wire
between
points
R
and
S
on
the
circuit
board
can
be
replaced
with
a
resistor
of
the
desired
value.
6-1
MAINTENANCE
6.1
Testing
Performance
of
the
Delay
Amplifier
6.1.1
Introduction
The
following
paragraphs
are
intended
as
an
aid
in
the
installation
and
checkout
of
the
Model
427.
These
instructions
present
information
on
front
panel
controls
and
waveforms
at
test
points
and
output
connectors.
6.1
.2
Test
Equipment
Test
following,
or
equivalent,
test
equipment
is
needed:
(1)
ORTEC
Model
419
Pulse
Generator
(2)
Tektronix
Model
580
Series
Oscilloscope
(3)
100-ohm
BNC
Terminators
(4)
Vacuum
Tube
Voltmeter
(5)
ORTEC
Model
410
Linear
Amplifier
(6)
Schematic
and
Block
Diagram
for
Model
427
Delay
Amplifier
6.1
.3
Preliminary
Procedures
(1)
Visually
check
the
module
for
possible
damage
due
to
shipment.
(2)
Connect
ac
power
to
the
Nuclear
Standard
Bin,
ORTEC
Model
401/402.
(3)
Plug
the
module
into
the
Bin
and
check
for
proper
mechanical
alignment.
(4)
Switch
on
the
ac
power
and
check
the
dc
power
supply
voltages
at
the
test
points
on
the
401
Power
Supply
control
panel
.
6.1.4
Delay
Amplifier
There
are
no
internal
adjustments
to
be
made
on
the
Model
427;
therefore,
testing
is
simply
a
matter
of
observation
of
the
input
and
output
waveforms.
(1)
Connect
the
output
of
the
Model
419
Pulse
Generator
into
the
input
of
the
Model
410
Amplifier.
(2)
Set
the
Model
410
controls
as
follows:
1
3
1
INPUT
ATTENUATOR
COARSE
GAIN
INTEGRATION
NEG
1.5
1
INPUT
POLARITY
FINE
GAIN
1st
DIFFERENTIATION
(outer
concentric
control)
1
2nd
DIFFERENTIATION
(inner
concentric
control)
427061566
6-2
(3)
Connect
the
bipolar
output
of
the
Model
410
to
the
INPUT
of
the
Model
427
through
RG-62/U
coble
and
terminate
the
cable
at
the
input
of
the
Model
427
with
a
100-ohm
terminator.
Ensure
that
all
DELAY
switches
are
in
the
OUT
position.
(4)
Vary
the
amplitude
of
the
Model
427
OUTPUT
by
adjusting
the
Model
419
Pulser;
there
should
be
no
distortion
of
the
signal
as
it
is
varied
from
0
to
10
volts.
(5)
Raise
the
output
amplitude
of
the
Model
419
until
the
Model
427
saturates;
the
saturation
level
should
not
be
less
than
11
volts.
(6)
Adjust
the
Model
419
for
a
10-volt
output
signal
from
the
Model
410
and
leave
it
at
this
setting
for
the
remainder
of
the
test.
(7)
The
output
of
the
Model
427
should
be
10
volts
and
should
come
promptly
with
respect
to
the
input
signal.
(8)
Switch
each
individual
delay
line
into
the
circuit
and
ensure
that
the
Model
427
output
remains
at
10
volts
and
is
delayed
the
appro
priate
amount.
(9)
Switch
al
l
delay
lines
into
the
circuit.
The
Model
427
output
should
be
approximately
11
volts
and
delayed
4.75
microseconds
from
the
input
signal
.
6.2
Changing
Amplifier
Gain
R22
The
gain
of
the
output
cable
driver
loop
is
given
by
the
ratio
of
]+Rl2'
gain
of
this
loop
can
be
changed
as
much
as
10%
by
increasing
or
decreasing
the
value
of
Rll
and
R12
without
any
adverse
effect.
Since
these
resistors
are
used
to
terminate
the
delay
lines,
it
is
rx)t
recommended
that
their
values
be
changed
more
than
10%.
6.3
Suggestions
for
Troubleshooting
In
situations
where
the
Model
427
is
suspected
of
malfunction,
it
is
essential
to
verify
such
malfunction
in
terms
of
simple
pulse
generator
impulses
at
the
input
and
output.
In
consideration
of
this,
the
Model
427
must
be
disconnected
from
its
posi
tion
in
any
system,
and
routine
diagnostic
analysis
be
performed
with
a
test
pulse
generator
and
an
oscilloscope.
It
is
imperative
that
testing
not
be
performed
with
a
source
and
detector
until
the
Delay
Amplifier
performs
satisfactorily
with
the
test
pulse
generator.
The
testing
instructions
in
Section
6.1
of
this
manual,
and
the
circuit
descriptions
in
Section
5
should
provide
assistance
in
locating
the
region
of
trouble
and
repairing
427061566
6-3
the
malfunction.
The
guide
plate
and
shield
cover
con
be
completely
removed
from
the
module
to
permit
oscilloscope
and
voltmeter
observations
with
a
minimal
chance
of
accidentally
short-circuiting
portions
of
the
etched
board.
The
Model
427
may
be
returned
to
ORTEC
for
repair
service
at
nominal
cost.
Stan
dard
procedure
requires
that
each
repaired
instrument
receive
the
same
extensive
quality
control
tests
that
a
new
instrument
receives.
6.4
Tabulated
Test
Point
Voltages
The
fo
llowing
voltages
indicate
the
typical
dc
voltages
measured
on
the
etched
cir
cuit
board.
In
some
cases
the
circuit
will
perform
satisfactorily
even
though,
due
to
component
variations,
there
may
be
some
voltages
that
measure
outside
the
given
limits;
therefore,
the
voltages
given
here
should
not
be
taken
as
absolute
values,
but
rather
are
intended
to
serve
as
an
aid
in
troubleshooting.
Table
6.1
Typical
DC
Voltages
NOTES:
1
.
All
voltages
were
measured
from
ground
with
digital
voltmeter
having
input
impedance
of
1
megohm
or
greater.
2.
Voltages
are
dc
values
with
no
input
pulses.
Location
Minimum
Maximum
+24V
Supply
23.99
24.01
+12V
Supply
11.99
12.01
-12V
Supply
-11
.99
-12.01
-24V
Supply
-23.99
-24.01
Qle
5.8
6.5
Qlb
5.2
5.8
Qlc
-6.1
-7.3
Q2e
-6.7
-8.0
Q2c
10.2
10.8
Q3e
-5.4
-8.0
Q3c
-23.0
-23.5
Q4e
-11.8
-12.8
Q4b
-11.1
-12.1
Q4c
-1.1
-0.3
Q5b
-12.5
-13.5
Q5c
-15.0
-17.5
Q6e
-0.4
+1.0
Q6c
-11.7
-11.9
Q7b
0.2
1.7
Q7c
14.4
18.6
Q8b
13.6
14.1
Q8c
22.5
23.5
Voltage
across
R28
00
Voltage
from
Q8e
to
Q8b
0.5
4.0
427061566
BIN/MODULE
CONNECTOR
PIN
ASSIGNMENTS
FOR
AEC
STANDARD
NUCLEAR
INSTRUMENT
MODULES
PER
TID-20893
Pin
Function
Pin
Function
1
+3
volts
23
Reserved
2
—3
volts
24
Reserved
3
Spare
Bus
25
Reserved
4
Reserved
Bus
26
0—30
volts
oc
5
Coaxial
27
0-30
volts
oc
6
Coaxial
*28
+24
volts
7
Coaxial
*29
—24
volts
8
200
volts
dc
30
Spore
Bus
9
200
volts
dc
31
Carry
No.
2
10
+6
volts
*32
Spore
1 1
—6
volts
*33
115
volts
oc
12
Reserved
Bus
*34
Clean
Ground
13
Carry
No.
1
35
Reset
14
Spore
*36
Gate
15
Reserved
37
Spore
*16
+
12
volts
38
Coaxial
*17
—12
volts
39
Coaxial
18
Spore
Bus
40
Coaxial
19
Reserved
Bus
*41
115
volts
oc
20
Spore
*42
Dirty
Ground
21
Spore
G
Ground
Guide
Pin
22
Reserved
*These
pins
are
inslailed
and
wired
in
parallel
in
the
ORTEC
Model
401
Madular
System
Bin.
The
transistor
types
installed
in
your
instrument
may
differ
from
those
shown
in
the
schematic
diagram.
In
such
cases,
necessary
replace
ments
can
be
made
with
either
the
type
shown
in
the
diagram
or
the
type
actually
used
in
the
instrument.
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