HP 8340b User Manual

SYTM
Peaking
Assembly-Level
Troubleshooting
THE
FAULT
ANNUNCIATOR COMES
ON
If
the
FAULT
annunciator
comes
on,
determine
the
function
that
caused
the
fault
as
follows:
1.
Press
[INSTR
PRESET] [SWEEPT1ME]
[1]
[SEC]
[SHIFT]
[MANUAL].
If
the
peak
or
tracking indicator
is
flashing,
the
peaking routine
failed
to
find a
peak
within the
range
of
the
SYTM
slope DAC.
This
can
be
caused
by:
a.
The
A28
SYTM
driver
assembly
may
not
be
shifting
the
passband.
b.
There
may
not
be
enough
power
from
the
SYTM
for
proper
ALC
operation.
c.
The
A16
ALC
modulator
may
be
defective.
If
the
instrument
won't
auto track properly
(no
fault
indication),
the
problem
may
be:
a.
The
ALC
loop
is
not
leveling.
b.
The
ALC
loop is
oscillating
during
leveling.
c.
The
YO
endpoints
are
off
(lock
and
roll
errors).
2.
Look at
the
CMP
test
point
(A28TP3)
for
an
indication
of
how
the
slope
DAC is
varying
slope
compensation
(see
Figure
H-4
for
a
typical
CMP
waveform).
If
the
waveform
is
incorrect,
the
A28
assembly
is
the
most
probable
fault.
3.
Check
the
MODLVL
test point
(A26TP3).
Refer
to
Figure
H-5
for
a
typical
MODLVL
waveform.
4.
Check the
MOD
test
point
(A26TP3).
See
Figure
H-6
for
a
typical
MOD
waveform.
If
either
the
MODLVL
or
MOD
signal
is
significantly
different
from
Figures
H-5
and
H-6,
the
most
probable
cause
is
the
A26
assembly.
5.
To clear
the
fault
annunciator,
press
[INSTR
PRESET],
or
turn
the
line
power
off
then
on.
-1.00000
s
0.00000
s
1.00000
s
^
^-
/
y
/"
A
/
/
"s
p^
•^1
^
~j .^
/
./"
y
^
/
\
^
r-
^
1-—
"sj
Ch
1
Timebase
100.0
mvolts,div
200
msfdiv
Offset
De
1
ay
250.0
muolts
-
0.
00000
s
Figure
H-4.
Typical
CMP
Waveform
HP
8340B/41B
SYTM
Peaking
Assembly-Level Troubleshooting
H-19

HP 8340b Specifications

General

Brand	HP
Model	8340b
Category	Inverter
Language	English