HP 6296A - Page 37

VOLTMEltR
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INDICATES
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INDICATES
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POWER
SUPPLY
OSCIUATOR
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ft
200
CD
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Figure
S-9.
Output
Impedance,
Test
Setup
b.
Set
METER
switch
to
highest
voltage
range
turn
CURRENT
controls
fully
clockwise,
and
turn
on
supply.
c.
Adjust
VOLTAGE
controls
until
front
panel
meter
reads
10
volts.
d.
Set
AMPLITUDE
control
on
Oscillator
to
10
volts
(Ein>.
and
FREQUENCY
control
to
lOOHz.
e.
Record
voltage
across
output
terminals
of
the
power
supply
(Eo)
as
indicated
on
AC
voltmeter.
f.
Calculate
the
output
impedance
by
the
following
formula:
EoR
Zout
=
Ein
- Eo
Eo
=
nns
voltage
across
power
supply
output
terminals.
R
=
1000
Ein=
10
volts
g.
The
output
impedance
(Zout>
should
be
less
than
0.001
ohm.
h.
Using
formula
of
step
f,
calculate
output
impedance
at
frequencies
of
lKHz,
lOOKHz,
and
lMHz.
Values
should
be
less
than
0.01
ohm,
0.2
ohm,
and
2
ohms,
respectively.
S-21
CONSTANT
CURRENT
TESTS
S-22
Load
Regulation.
To
check
the
constant
cur-
rent
load
regulation,
proceed
as
follows:
a.
Connect
test
setup
shown
in
Figure
5-4.
b.
Turn
VOLTAGE
controls
fully
clockwise.
c.
Set
METER
switch
to
highest
current
range
and
turn
on
supply.
d.
Adjust
CURRENT
controls
until
front
panel
meter
reads
exacUy
the
maximum
rated
output
cur-
rent.
e.
Read
and
record
voltage
indicated
on
dif-
ferential
voltmeter.
S-6
f.
Short
out
load
resistor
(Ry)
by
closj.ng
switch
Sl.
g. Reading
on
differential
voltmeter
should
not
vary
from
reading
recorded
in
step
e
by
more
than
the
following
{variations
expressed
in
mVdc):
•
Model
6282A 628SA 6286A
6290A
6291A li296A
Variation
:1.:0.
60
:1:2.
20
:1.:0.
60 :t0.830
:t0.70
:1::0.830
5-23
Line
Regulation.
To
check
the
line
regula-
tion,
proceed
as
follows:
a.
Utilize
test
setup
shown
in
Fiqure
5-4
leaving
switch
Sl
open
throughout
test.
b.
Connect
variable
auto
transformer
b1!tween
input
power
source
and
power
supply
power
input.
..
·:
·
c.
Adjust
auto
transformer
for
lOSVAC
input.
d.
Turn
VOLTAGE
controls
fully
clockwise.
e.
Set
METER
switch
to
highest
current
range
and
tum
on
supply.
f. Adjust
CURRENT
controls
unW
front
panel
meter
reads
exactly
the
maximum
rated
output
cur-
rent.
g.
Read
and
record
voltage
indicated
(Jn
dif-
ferential
voltmeter.
h.
Adjust
variable
auto
transformer
fo1~
125
VAC
input.
i.
Reading
on
differential
voltmeter
sltlould
not
vary
from
reading
recorded
in
step
9
by
more
than
the
following
{variations
expressed
in
mVdc):
Model
6282A 628SA 6286A
6290A
6291A 6296A
Variation
:1:0.60
:1:2.20
:t0.60 :t0.830 :tQ.70 :i:0.830
5-24
Ripple
and
Noise.
To
chec~
the
ripple'
and
•
noise,
proceed
as
follows:
a.
Use
test
setup
shown
in
Figure
5-<I.
ex-
cept
connect
AC
voltmeter
across
sampling
resistor
instead
of
differential
voltmeter.
b.
Rotate
VOLTAGE
controls
fully
cloc:kwise.
c.
Set
METER
switch
to
highest
currei~t
range
and
turn
on
supply.
d.
Adjust
CURRENT
controls
until
front
panel
meter
indicates
exactly
the
maximum
rated
output
current.
e.
Turn
range
switch
on
AC
voltmeter
to
lmV
position.
f. The
AC
voltmeter
should
read
as
f<>llows:
{Readings
are
expressed
in
mVac)
Model
6282A 628SA 6286A
6290A
6291A
li296A
Reading
O.SO
0.60 0.50
1.
0
0.
6
1.
0
S-25
TROUBLESHOOTING
S-26
Components
within
Hewlett-Packard
power
supplies
are
conservatively
operated
to
provide
maximum
reliability.
In
spite
of
this,
parts
with-
in
a
supply
may
fail:
Usually
the
instrument
must
be
immediately
repaired
with
a minimum
of
"down
time"
and
a
systematic
approach
as
outlined
in
succeeding
paragraphs
can
greatly
simplify
and
•
speed
up
the
repair.