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Tektronix FG 5010 User Manual

Tektronix FG 5010
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Maintenance
-
FG
5010
GENERAL
TROUBLESHOOTING
Introduction
The
front
panel
error
codes
help
to
isolate
the
difficulties
.
After
the
trouble
is
isolated
,
review
the
schematics
and
cir
cuit
description
as
aids
in
finding
the
difficulty
.
Signatures
for
the
CPU
,
serial
shift
registers
and
some
logic
in
the
Loop
2
and
Sine
Shaper
circuitry
are
included
in
this
manual
.
Sev
eral
troubleshooting
techniques
for
the
analog
circuitry
on
Loop
1
and
Loop
2
boards
are
also
included
.
Analog
type
troubleshooting
techniques
are
usable
on
the
Sine
Shaper
,
Output
,
Display
Driver
,
Interconnect
,
and
Front
Panel
circuit
boards
.
Loop
1
Troubleshooting
Remove
jumper
P1435
.
Location
of
this
jumper
is
shown
on
the
Adjustments
Location
illustration
for
the
Loop
1
board
in
the
pullout
pages
at
the
rear
of
this
manual
.
Ground
the
collectors
of
Q1432
and
Q1340
.
Connect
a
variable
dc
voltage
source
(
±
1.1
V
)
from
ground
to
the
capacitor
side
of
jumper
P1435
(
across
C1432
)
.
Connect
an
oscilloscope
to
the
emitter
of
Q1332
,
the
output
of
the
triangle
buffer
.
Now
vary
the
voltage
source
from
approximately
+1.1
V
to
-1.1
V.
The
voltage
at
the
oscilloscope
should
smoothly
track
the
voltage
source
changes
.
This
proves
proper
oper
ation
of
the
triangle
buffer
.
Connect
the
oscilloscope
probe
to
either
pins
13
or
14
of
U1351A
,
the
level
detector
circuit
ry
.
One
output
is
the
complement
of
the
other
.
Again
,
vary
the
voltage
source
from
+1.1
V
to
1.1
V.
Look
for
a
high
to
low
400
mV
voltage
change
at
the
output
pins
.
Satisfac
tory
operation
indicates
the
level
detector
is
operating
properly
.
To
check
the
level
shifter
and
transistor
bridge
,
substitute
a
current
meter
for
the
short
from
the
collectors
of
Q1432
and
U1340
to
ground
.
Vary
the
voltage
source
between
+1.1
V
and
1.1
V
and
observe
the
current
me
ter
.
The
meter
should
indicate
first
one
current
polarity
and
then
the
other
as
the
voltage
source
is
varied
.
Cal
Mode
Troubleshooting
Troubleshooting
the
frequency
control
circuits
can
also
be
done
in
the
Cal
mode
.
The
FG
5010
goes
into
the
Cal
mode
by
setting
the
mode
strap
on
the
rear
of
the
CPU
board
(
J1121
)
to
the
Cal
position
.
The
instrument
must
then
go
through
a
power
-
on
cycle
to
enter
the
Cal
mode
.
The
differences
between
the
Cal
and
Normal
mode
are
:
1.
The
automatic
frequency
control
is
disabled
.
The
fre
quency
D
/
A
is
always
set
to
4000
(
decimal
)
at
the
top
of
each
range
.
For
example
,
2.000
MHz
will
set
the
frequency
D
/
A
to
4000
,
1.000
MHz
will
set
it
to
2000
,
and
200.1
kHz
will
set
it
to
400.
In
the
VCF
mode
,
the
frequency
D
/
A
may
be
set
to
zero
by
setting
the
frequency
to
zero
.
7-14
2.
Both
frequency
D
/
As
and
both
symmetry
D
/
As
may
be
set
to
zero
by
a
RECALL
command
.
These
D
/
As
may
be
restored
by
a
RECALL
1
command
or
by
turning
the
VCF
mode
off
.
3.
The
automatic
range
switching
in
the
PH
LOCK
mode
is
disabled
.
To
select
a
desired
frequency
range
or
phase
lock
filter
,
go
to
CONTinuous
mode
,
program
a
frequency
in
the
desired
range
,
then
go
to
PH
LOCK
mode
.
4.
The
message
delimiter
switch
on
the
rear
of
the
in
strument
is
used
in
the
Cal
mode
to
stop
the
power
-
on
self
test
when
the
first
error
is
detected
.
Set
the
message
delimiter
switch
to
the
LF
/
EOI
position
to
stop
the
self
test
on
the
first
occurrence
of
an
error
.
This
leaves
the
instru
ment
hardware
in
the
state
where
the
fault
was
detected
.
To
resume
execution
of
the
self
test
,
press
the
ID
key
.
5.
While
the
SLOPE
setting
is
negative
,
the
frequency
of
the
main
loop
is
measured
by
the
frequency
control
logic
on
the
Loop
2
board
approximately
every
30
ms
.
The
frequen
cy
D
/
As
on
the
Loop
1
board
are
not
changed
to
correct
for
frequency
errors
.
This
is
done
to
allow
for
troubleshooting
of
the
frequency
control
logic
on
Loop
2
.
While
the
SLOPE
setting
is
positive
,
the
frequency
of
the
main
loop
is
measured
whenever
the
manual
trigger
key
is
pushed
.
This
is
used
for
triggering
single
shot
measure
ments
by
the
frequency
control
logic
on
Loop
2.
After
each
measurement
is
made
,
the
number
of
counts
in
the
refer
ence
frequency
counters
(
U1320
and
U1322
Loop
2
)
is
dis
played
on
the
front
panel
readout
.
The
number
of
main
loop
cycles
over
which
the
measurement
is
made
can
be
calculat
ed
by
multiplying
the
frequency
setting
(
in
Hertz
)
by
0.005
.
The
result
of
this
should
then
be
rounded
off
to
the
nearest
integer
.
If
this
number
is
exactly
half
way
between
two
inte
gers
,
it
should
be
rounded
to
the
nearest
even
integer
(
i.e.
,
5.5
rounds
to
6
,
and
8.5
rounds
to
8.
)
Loop
2
Troubleshooting
The
following
procedure
checks
the
trigger
-
gate
input
amplifier
,
the
phase
detector
,
charge
pump
,
phase
lock
fil
ter
,
and
over
and
under
-
range
detectors
.
Place
the
FG
5010
in
the
Cal
mode
.
This
is
accomplished
by
moving
jumper
P1121
,
located
on
the
CPU
board
,
to
the
Cal
position
and
powering
up
the
instrument
.
See
the
CPU
board
Adjustment
location
illustration
for
the
location
of
this
jumper
.
Upon
power
up
,
the
display
reads
CAL
,
then
1
kHz
)
REV
JAN
1982
U
U
U
U
U
U
U

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Tektronix FG 5010 Specifications

General IconGeneral
BrandTektronix
ModelFG 5010
CategoryPortable Generator
LanguageEnglish

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