Advertisement
Model 5245L
Table
6-4.
Povrer
Supply
Voltages
Test
Point
Line Voltage
Adjustment
103
115
t27
A6(15
)
A6(12)
A7(13)
A7(4)
A16(11)
A7(B)
A?(10)
-120
xlT1a
+160 r10%
-
15
t.5
+
13
t.5
+
20
t.5
-6.9 +
1
+1?.6
+
1
-130t
1070
+
1?0
+
lj7o
-
15
t.5
+
13
t.5
+
20t.5
-6.9
r
1
+17.6
t
1
-150 xlT7o
+180
+107o
-
15
t.5
+
13
+.5
+
20
t.5
-6.9
*
1
+17.6
+
1
None
None
R5
Rl2
Rl?
Depends
on
adjustment
of +20vdc
and
-1Svdc
above
6.19.
INPUT AMPLIFIER
A19.
6-20.
The following procedure sets the output level
and
checks the
gain, frequency response,
and
sensi-
tivity
of the input amplifier.
a.
Turn
counter on
and
set
L
E
V
E
L
to
PRESET.
b.
With
no
input
connected, measure
the output
dc
voltage
at
A19(6).
c.
Adjust dc voltage with
A19R20
to
+6.3V +.
2V.
d.
Connect
outputof Test Oscillator to Counter
DC
INPUT connector with
50-ohm
termination
at
Counter.
e.
Set
Test Oscillator
output
to
50
MHz
at
100 mV
rms.
f.
Check output
at
A19(6)
with Oscilloscope;
output
should
be 1.5V p-p minimum.
g.
Increase output
of
Test Oscillator
to
3V
rms.
Theoutput at
.4'19(6)
is
asymmetrically
clipped wave-
form approximately
2V
p-p.
h.
Set
SENSITIVITY
to .1V,
TIME
BASE
to
10 ms,
and
FIJNCTION
to
FREQUENCY.
i.
Set
Test Oscillator output
to
50
MHz
at
100 mV
rms.
j.
AdjustA19R20
until correct
count
appears.
Re-
duce
input signal amplitude and readjust A19R20
for
mu<imum
sensitivity.
6-2
1.
6-22.
Change
RATIO INPUT
AMPLIFIER
A2O.
Repeat
steps
a
through
g in
Paragraph 6-20.
A19(6)
to
A20(6).
Section
VI
Paragraphs 6-19 to
6-33
b.
Conneet
output
of Test Oscillator
50
MHz
at
100
mV
to
Counter
EXT. TIME BASE through
50-ohm
termination.
c.
Adjust
A20R20
until
correct count appears. Re-
duce input signal amplitude
and
readjust
A20R20
for
maximum sensitivity.
6-23.
FUNCTION CONTROL
A21
a.
Set
TIME
BASE
to.1
prs
and
FUNCTION
to
1
PERIOD
AVERAGE.
b.
Set
Test Oscillator
to
1.5 MHz at
100
mV
and
connect
to the Counter AC SIGNAL INPUT connector.
c.
Observe
correct
count on
counter.
Reduce the
Test Oscillator
output
and
adjust
A21R31
for
maximum
sensitivity.
Note
Do not
change
the setting of the
output
Ievel control
A19R20.
6-24.
TROUBLESHOOTI NG.
6-25.
TROUBLESHOOTING AIDS.
6-26.
OPERATING
MANUAL.
The
Operating
Manual
provided with
the HP 5245L
provides general informa-
tion
about the
instrument
and
its capabilities.
Refer
to
the
Operating Manual
for
specifications, installa-
tions, step-by-step
operating procedures,
and
a quick
operator's
check
of instrument operation.
6-27.
PRINCIPLES OF
OPERATION. SectionII pro-
vides valuable information
on how
the
instrument
and
its circuits
function.
6-28.
SCHEMATIC DIAGRAMS.
Schematic
diagrams
and a
block diagram are provided
in
Section Vtr.
6-29.
COMPONENT
LOCATION.
Photographs are
provided
with the
schematic diagrams
to
aid in lo-
cating
components
on switches
or circuit
boards.
6-30.
TROUBLESHOOTING
"T
R E
E".
A
step-by-
step troubleshooting procedure
is
provided
on
pages
6-10 through
6-13.
This
procedure
is
based on the
self
check
feature of
the
instrument
and
makes max-
imum use of front panel controls
and
indicators.
6-31.
SELF CHECK
TABLES.
Table 6-8
provides
33 unique combinations
of
Go-No
Go
situations pos-
sible in the Self Check
function. Circuit
elements
to
be
checked
are indicated for
each
combination. Table
6-6
lists
assemblies
checked
in
Self
Check
functions.
6.32.
TROUBLESHOOTING PROCEDURE.
6-33.
MALFUNCTION
AT
TURN
ON.
If
counter
fails
to turn
on
(no
display,
decimal point,
or
measurement
units) make the following
checks:
a.
Line voltage switch set
for
power source.
b.
Power cord
plugged
into
counter
and power
source.
c.
Line fuse
good.
d.
Ac power available at source.
e.
Power supply (.4,6, A7,
T2, L1, L2,
C5).
6-3
a.
Set SIGNAL INPUT SENSITIVITY
to
1V range,
TIME
BASE
to
EXT.,
AIID FIINCTION
to
1 PEzuOD
\
AVERAGE.
SCt
OUTPUT
STANDARD FREQUENCY
(rear
panel)
to
100
Hz.
Connect
a coaxial cable from
OUTPUT
STANIDARD FREQUENCY
(rear
panel)
to
AC
SIGNAL
INPUT (front
panel).
02349-1
Advertisement
