Table of Contents
Model
8672A
Service
SECTION
VIII
SERVICE
8-1.
INTRODUCTION
8-2. This section provides
information
on
service
related
subjects.
Safety
considerations
include
warnings and cautions
to
be observed
while
servic¬
ing
the
instrument.
The
arrangement
of
the
princi¬
ples
of
operation
and
troubleshooting
is
explained.
Repair information
such
as
non-repairable items,
module exchange
and disassembly and reassembly
procedure
are included.
8-3. The
service sheets are in
the
foldout
section.
Each
service sheet
includes
a
block or schematic
diagram,
with
accompanying principles
of
opera¬
tion
and
troubleshooting information. Usually
a
component
location
diagram
is
also
included.
Figure 8-1 Schematic Diagram Notes provides
gene¬
ral
information which
relates
to block and
sche¬
matic
diagram symbols.
8-4.
Other pertinent
service
information
is
included
throughout the section.
8-5.
SAFETY CONSIDERATIONS
8-6. This section contains warnings and cautions
which
must be followed
for your protection
and to
avoid damage
to the equipment.
["WARNING
]
Maintenance
described
herein
is
per¬
formed
with
power supplied
to the
in¬
strument and with protective
covers
re¬
moved.
Such
maintenance should
be
performed only
by
service-trained
per¬
sonnel who are aware
of
the hazards
involved.
Where
maintenance
can
be
performed
without power
supplied, the
power should
be
removed.
8-7.
Any
adjustment, maintenance, and repair
of
the
opened instrument under voltage should be
avoided
as
much
as
possible and,
when inevitable,
should
be carried
out only by
a
skilled person
who
is
aware
of
the hazard involved.
8-9. Make
sure
that only
fuses
with
the required
rated
current
and
of
the specified type (normal
blow, time delay,
etc.) are used
for replacement.
The
use
of
repaired
fuses
and the
short-circuiting
of
fuseholders must be avoided.
8-10. Whenever it
is
likely that
this
protection
has
been
impaired, the instrument must
be
made
in¬
operative and
be secured against any
unintended
operation.
8-11.
PRINCIPLES
OF
OPERATION
8-12. The operation
of the
Synthesizer
is
explained
on each service sheet. Overall operation, in terms
of
interaction of the major
assemblies,
is
found
on
Service Sheet
1.
Each major
assembly,
is
broken
down into
sections (groups
of
assemblies)
on
Ser¬
vice Sheets
2,
3
and 4. Remaining service
sheets
re¬
view the
section
operating information and explain
the
assembly
operation to the
stage
(group
of
com¬
ponents) level.
8-13.
TROUBLESHOOTING
NOTE
If
the Synthesizer
malfunctions,
begin
troubleshooting on
Service Sheet
1.
8-14. Arrangement
in
Manual
8-15. The
troubleshooting
information for the
Synthesizer
is
found
on each service sheet.
If
the
Synthesizer malfunctions,
begin
troubleshooting
with
Service
Sheet
1
to
isolate
the defect to
a
major
assembly.
On
Service Sheets 2, 3, and
4,
troubleshoot to the
section level (a logical group
of
assemblies).
Next,
isolate the defective assembly
by following the information
on the key Service
Sheet
for the
section.
With
the remaining informa¬
tion
on
the key
service sheet
(which
applies to the
assembly) on the remaining service
sheets, isolate
the defective
stage.
Continue troubleshooting to
defective component.
8-8. Capacitors inside the instrument
may
still be
charged even
if
the
instrument
has
been discon¬
nected
from
its source
of
supply.
8-16.
Supplemental Troubleshooting Aids
8-17. The HP-IB
Diagnostic Program
may verify
that the HP-IB input to the Synthesizer
is
operat-
8-1
Table of Contents
