Section
V
Model 333A/334
lem. Theseoperations should
be
undertakenonly after
it
has
been established that the difficulty cannot
be
eliminated
by
the Adjustment and Calibration Proced-
ures.
An investigation should also
be
made
to
insure
that the trouble
is
not
a
result of conditions external
to
the
333A/334A.
5-35. Conduct
a
visual
check
of
the 333A/334Afor
possible burned
or
loose
components, loose connec-
tions,
or
any other
obvious
condition which might
suggest
a
source
of
trouble.
THE 333A/334A CONTAINS
VERY
HIGH
IMPED-
ANCE.
HIGH
FREQUENCY CIRCUITS.
CON-
TAMINATIONOFTHE SWITCHES,
CIRCUIT
BOARDSOR
TUNXNGCAPACXTORWILL CAUSE
HIGH
IMPEDANCE LEAKAGE PATHS AND
SUBSEQUENT DETERIORATION OF THE
PERFORMANCE OFTHE
INSTRUMENT.
AVOIDTOUCHINGANYOFTHESE CIRCUITS
WITH THE
BARE
FINGERS, AS
SKIN
OILS
ARE
EXTREMELY CONTAMINATING.
5-36. Table 5-8 contains
a
list
of
typical front panel and
internal trouble symptoms,
as
well
as
the probable cause
oftrouble.
If
the instrument malfunction cannot
be
loca-
tedthrough
use
of
the table, refer to Paragraphs 5-38
through 5-44.
I
COMPONENT
A2C22*
A2C23*
A2C30*
A2C29*
A2R30*
A3Cll*
A3R17*
c9
*
Ft3*
S3R14*
S4R6*
through
S4Ft26*.
5- 37. Trouble
in
the Model 333A/334A can generw
be isolated to circuits
of
one
of
the
two
principu
instrument functions-voltmeter
or
distortion.
order for the distortion function to Operate
properly,
the voltmeter function must operate properly. There-
fore, troubleshoot the voltmeter function
first
to
assure that
it
works normally before attempting
ta
locate
a
trouble
in
the
distortion function.
558. TROUBLESHOOTING VOLTMETER
FUNCTION.
5-39. Follow the steps below
to
troubleshoot the
volt.
meter function:
a.
b.
C.
Set
333A/334A controls
as
follows:
FUNCTION
.
.
.
.
.
.
.
.
. .VOLTMETER
Connect
a
1
V
rms,
1
lrHz
signal
to 333A/
334A
INPUT
TERMINALS.
METER RANGE.
. .
.
.
1
VOLT
Measure ac
output
of
impedance converter
at A2-pin 4 for approximately
1
mV
rms
(Use
10 M51/10 pF impedance probe),
If
proper
signal
is
present, proceed to step c;
if
not proceed
to
step
d.
Measure
ac
input
to meter amplifier at A2-
pin 6for approximately
1
mVrms.
If
proper
signal
is
present, check meter amplifier
circuit.
(See schematic diagram
of
Fig-
Table 5-7. Factory Selected Components
FUNCTION
Sets
range of A2C21
Adjusts meter frequency response
in
2
MHz
region
Adjusts meter frequency response
in 20 Ha region
Adjusts meter flatness on
0.0003
V
range at 300
lcHz
Adjusts meter amplifier gain on
0.0003
V
range
at
400 Hz.
Adjugts bridge amplifier frequency
response in
1
MHz to
3
MHe
region
Adjusts
gain
of
rejection amplifier
Adjusts tracking
of
frequency
dial
Adjusts
range
of S2R8
Adjusts flatness
of
1OOO:l
atten-
uator
in
2
MHz
to
3
M?iz
region
Must be individually matched
to
be
f
1/48
Low
0
PF
100 pF
10 pF
0
PF
15051
56 pF
1
k51
0
PF
051
7.551
--
VALUE
Normal
47 pF
240
pF
22
pF
390 pF
30051
127 pF
2
k52
2.2
pF
39052
100
--
High
47 pF
320 pF
50
pF
680 pF
300
SZ
127 pF
3
k51
6.8 pF
39051
1051
5-12
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