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Section
V
5.72.
TBOUBLESHOOTING.
5-73. This
portion of
Section
V
contains
infoflnation
and
procedures
desigled
to
assist
in
thc
isolation
of
ntalfunc-
tions. The information
prescntcd
is
based
on
a
systematic
analysis
of
the
instrument circuits and,
if
followed,
will
rninirnize troubleshooting time.
5-74.
Guidelines.
5-75.
Before troublcshooting
the
35754,
obscrve
the
fol-
lorving guidelines:
a.
Pcrforrn
thc
adjustrnents
outlined in
Paragraphs 5-25
through 5-48.
Some apparent
rrallunctions
oan
bc
cor-
rected
by
thcse
adjustmcnts
or
the inability to
obtain
correct
adjustnrent
will
often
reveal
the
source
of
trouble.
b.
Check
thc
power
supplies (Pafagraph
5-27)
before
troubleshooting other
sections.
c.
Check
lor
burned
or
loose
cornponents,loose
connec-
tions
or
any
other
obvious
condition
that might
be
a
source
of trouble.
5-76.
Symptoms.
5-77.
Obtair
as
mrny front
panel symptoms as
possible.
Check
the
perforruance
ol
the
3575A and
obtain
the
lcrllorving
failure information
:
a.
Does
the
trouble affect
arnplitude
readings?
If
yes,
disegard
phase
and
refer
to
the Arnplitude Troubleshooting
Tree (Figure
5-8). The
Amplitude Troubleshootilg
Tree
will
help isolate the trouble to
a
stage
or component or
will
Iead
to
the
Digital Parel Meter
Troubleshooting
Tree
(Figure 5.9).
b.
Does
the
trouble
affect
pllase readillgs
only'!
lf
yes,
refer
to
the
Phase
Troubleshooting
Tree (F'igure
5-10).
The
Phase
Troubleshooting
Tree
will
help isolate the trouble to
a
stage
or
component
or will
lead
to
the
Phase
l,ogic
Troubleshuoring
Trcc
(Figurc
5-l
l).
5'78.
Trouhleshootinq
Trees.
5'79. The
iour
t
rolr
blc
slt
ooling
trees, FiBure
5-8
through
5-11, are located
on
fold{uts at
tlre cnd
oI
tl]is
seotion.
Mrcn
entering
a
troubleshooting
trcc,
always
start
at
the
point
labeled
"START". Do not attempt
to
start
in
the
middle
of
a
tree.
Chccks
outlined
in
each
troubleshooting
tree
will
lead
to
anothcr troubleshooting tree
or
to
one
of
the
following:
"Probable
Cause"
"Recheck Symptoms"
5-80. 'Probable
Cause."
The
"Probable
CaLrse" inftrr-
mation
only
indicatcs
rhe
urost
likell
lailurc
areas
and
dcsignatcd components are
not
neccssarily
the
exact
cause
of
trouble.
The
"hobable
Cause"
infonuation
should
bc
s-t
8
Model
3575A
used
in
conjunction
with
the
voltages
and waveforms on
the
schematic
diagrams
to
further pinpoint
the
source
of
trouble.
5-81. "Recheck Symptoms."
The
"Recheck
Symptoms"
blocks indicate
that
preceeding checks
do
not
reveal any
specific
malfunction.
When
confronted
with a
"Recheck
Symptom" block,
recheck
the
performance
of
the instru-
ment
to
verify that
the
original
symptom
is
still
present.
If
the original symptom
persists,
repeat the
checks
outlined
in
the
troubleshootillg trees
while watching
for
marginal
indications.
If
the
trouble still
cannot
be
localized, trouble-
shoot
using the
yoltages
atd
waveforms
on the
schematic
diagrans. Contact
the
nearest
-hp-
Servicc
Office
or
(bstomer
Service
facility if
assistance
is
required.
5-82.
Measurement
Conditions.
5-83.
The
voltages
and waveforms shown
on
the scllentatics
and troubleshooting
trees
were obtained
with a
I
V
rms
(+
6
dBV), I
kllz
sine wave applied
to
both
inputs.
If
symptoms
do not
appear
with
2
Vrms, I kHz
inputs,
troubleshoot
using
inputs
that
produce
symptoms.
Keep
thc
input
level
as
high
as
possible
and
the input
frequency
as close
to
I
kllz
as possible.
Note
that
some
of
the
waveshapes
and voltages
may
differ
when
inputs other thalr
2
V mrs,
I kllz
are used.
5-84.
Control
Settings.
5-85.
When using the troubleshooting
trees
with
2
V
rms,
1
kllz
inputs, the
3575A
controis
should be
set
as
follorvs;
DISPLAY
....AMPLITUDE
(for
arnplitude problem)
DISPLAY
......
...PHASE
(for
phase
probtem)
AMPLTTUDE
FUNCTION..,
......
. A
(or
as
specified)
Voltage
Range
.
0.2
mV
-
2
V
(both
channels)
FREQUNECY RAh\GE
.
l0 tlz
-
100
kHz
PHASEREFERENCE,....
-......+A
(or
as
specified)
5-86.
Power
Supply Troubleshooting.
5-87.
The
3575A
contains
six
major power
supplies
that
lirrnish
regulated
voltage
to
thc
various
assemblies
through-
out the
instrument.
The
raw
supplies
a-re
located
on
the
Power Supply
Mother Board, A15, and the
regulator
circuits
for
these supplies are
located on the
Power Supply
Asscmbly,
Al,+.
ln
addition, the
IJ)g Converter
Assemblies,
A3
and A4,
contain
separate
regulator circuits which
supply
+
2
Vdc to
the
Hybrid
lrg
Amplifiers.
The +
2
V
regulators
receive preregulated voltage
from the
+
3.8
Vdc
supply on
A14.
5-88.
Before
troubleshooting
the 3575A,
perform
the
+
12
V
Reference
Adjustnent
(Paragraph
5-25) and
check
the
power
supply
voltagcs
as
outlined
in
Paragraph 5-28.
TBOUBLESHOOTING
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