HP 6296A - Page 44

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Table
5-8.
Checks
and Adjustments After Replacement of Semiconductor
Devices
(Continued)
CR600,
CR601,
.Voltage
across
appro-
CRBOO,
CRBOl,
Rectifier
diodes
priate
filter
capacitor
CRS01-CRS04
Reference
voltages
Check
+9.
4V
and
-6.
2V
VR600,
VR601
reference
voltages
Table
5-9.
Calibration Adjustment Summary
Adjustment
or
Calibration
Meter
Zero
Voltmeter
Tracking
Ammeter Trac king
•voltage"
Programming
Current
•current"
Programming
Current
Overvoltage Trip
Transient
Response
Preregulator
Tracking
S-36
ADJUSTMENT
AND
CALIBRATION
S-37 Adjustment and
calibration
may
be
req\lired
after
performance
testing,
troubleshooting,
or
repair
and
replacement.
Perform
only
those
adjustments
that
affect
the
operation
of
the
faulty
circuit
and
no
others.
Table
S-9
summarizes
the
adjustments
arid
calibrations
contained
in
the
following
paraqraphs.
5-38
METER
ZERO
S-39
Proceed
as
follows
to
zero meter:
a.
Tum
off
instrument
(after
it
has
reached
normal
operating
temperature)
and
allow
30
seconds
for
all
capacitors
to
discharge.
b.
Insert
sharp
pointed
object
(pen point or
awl)
into
the
small
indentation
near
top
of
round
black
plastic
disc
located
directly
below meter face.
c.
Rotate
plastic
disc
clockwise
(cw)
until
meter
reads
zero,
then
rotate
ccw
slightly
in
order
to
free
adjustment
screw
from meter
suspension.
If
pointer
moves,
repeat
steps
band
c.
5-40
VOLTMETER
TRACKING
S-41
l'o
calibrate
voltmeter
tracking,
p-oceed
as
follows:
S-13
Paragraph
Control
Device
5-38
Pointer
5-40
R870
and
R865
5-42
R855
S-44
.R806
5-46
R808
5·48
R604
s-so
R307
5-52
R7ll
a. To
electrically
zero
meter,
set
METER
sWitch
to
highest
current
position
and,
With
supply
off
and
no
load
connected,
adjust
R870
until front
panel
meter
reads
zero.
b.
Connect
differential
voltmeter
across
sup-
ply,
obs Erving
correct
polarity.
c.
Set
METER
switch
to
highest
voltage
range
and
turn
on
supply.
Adjust
VOLTAGE
control until
differential
voltmeter
reads
exactly
the
maximum
rated
output
voltage.
d.
Adjust
R865
until
front
panel
meter
also
indicates
maximum
rated
output
voltage.
S-42
AMMETER
TRACKING
5-43
To
calibrate
ammeter
tracking,
proceed
as
follows:
a.
Zero meter
as
described
in
step
a of
5-41.
Connect
test
setup
shown
on
Figure
5-4
leaving
switch
Sl
open.
b. Turn
VOLTAGE
control
fully
clockwise
and
set
METER
switch
to
hiqhest
current
range.
c. Turn
on
supply
and
adjust
CURRENT
con-
trols
until
differential
voltmeter
reads
1.
OVdc.
d. Adjust
R855
until
front
panel
meter
indi-
cates
exactly
the
maximum
rated
output
current.