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Model 5254C
Section
V
SECTION
V
MAINTENANCE
5-1.
INTRODUCTION.
5-2.
This
section
provides maintenance and service
information
for the
Model 5254C Frequency
Converter.
Included are a periodic
maintenance procedure,
a
table
of
recommended
test
equipment, an in-cabinet
performance
check which
may
be used
to
verify
proper
operation
of
the
frequency
converter, troubleshooting
procedure, and repair and adjustment procedure.
5-3.
PERIODIC
MAINTENANCE.
5-4.
No
special
maintenance procedures are required
when
the
converter
is
operated
in
normal
environments.
However,
if
unit
is
subjected
to
operation
in
extremely
dusty
environments,
periodically clean
all
gears
with
a
lint-free cloth
and apply
a coating
of light,
petroleum
base,
open-gear grease
to
all
gear
teeth.
5-5.
TEST
EQUIPMENT.
5-6.
Recommended
test
equipment
for
performance
checking, troubleshooting
and
circuit
adjustment
after
repair
is
listed in
Table
5-1.
Other
test
instruments
may
be used
if
their specifications
equal or
exceed
the
required
characteristics.
5-7.
IN-CABINET
PERFORMANCE
CHECK.
5-8.
The
following
performance
check (Table
5-4)
verifies
proper
operation
of
all
circuits
in
the
Model
5254C and
may
be
used:
a.
as part
of
an incoming
inspection
check
of
instru-
ment
specifications;
b.
periodically, for
instruments used
in
systems
where
maximum
reliability
is
of
utmost importance;
c.
as part
of
a troubleshooting
procedure
to
locate
malfunctioning
circuits,
and
d.
after
any repairs or adjustments, before return-
ing
instrument
to
regular service.
5-9.
TROUBLESHOOTING.
5-10.
Refer
to
Section
IV,
Principles
of
Operation,
for
information on
the
operation
of circuits.
Table
5-2
gives
the
reference
designations
of
assemblies used
in
the
converter and
their
corresponding nomenclatures.
Figure
5-2
shows
the location
of all
assemblies used
in
the
Model
5254C.
Figures 8-2 and 8-3
show
com-
ponent
location
on
the
assemblies. Table
8-1,
Trouble-
shooting Aids, gives information on
waveforms
and
dc voltages
which are present
when
circuits
are oper-
ating
properly.
The waveforms
are referenced
to
test
points
throughout
the
converter.
These
test
points
are keyed
to
the
schematic diagrams, Figures 8-2
and
8-3.
Table
5-2.
Assembly
Designations
A1
MULTIPLIER AMPLIFIER
A
2
HARMONIC
GENERATOR
A3
MIXER
A4
LOW
PASS
FILTER
A5
VIDEO AMPLIFIER
5-11.
MULTIPLIER AMPLIFIER ASSEMBLY
Al.
5-12.
If
the Multiplier
Amplifier
Assembly
is
sus-
pected
of
being
faulty,
use
the
test
points
on
the
sche-
matic diagram, Figure
8-2,
and the
test
points
and
dc voltages given
in
Troubleshooting
Aids,
Table
8-1,
in
the
following
order
7, 1,
2, 3, 4, 5,
and
6 to
help
isolate the faulty
circuit.
5-13.
MIXER ASSEMBLY
A3,
5-14.
A
faulty
mixer assembly
is
usually indicated
by poor
sensitivity,
noisy
signal output
from
the
video
amplifier.
If
the
mixer assembly
is
suspected
of
being
faulty,
remove
amplifier
side plate
(MP12), see Fig-
ure
5-2,
and
perform
the
resistance
check
given
in
Table
5-3.
Table
5-3.
Mixer
Resistance
Check
—
Check
Connect
Ohmmeter
(fy
41
2
A
only)
Ohmmeter
Scale
Reading
Ohms
Lead
Common
Lead
i
A3R3
Ground
XI
Greater
than
10K ohms
2
Ground
A3R3
X1K
600
-
1200
ohms
3
A3R4
Ground
XI
600
-
1200
ohms
4
Ground
A3R4
X1K
Greater
than
10K ohms
Note:
These
measurements
can be
made
with
the
Mixer
Assembly
installed
in
the
instrument and
without
unsoldering any wires.
5-1
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