HP 5300A - Instrument Access

Me
Model 5300A
Maintenance
5-5. INSTRUMENT ACCESS
5-6.
For
access
to
mainframe
assembly,
separate
the
5300A
from
plug-on
used
as
follows:
a.
Turn
ac
power
OFF
and
disconnect
power
cord.
b.
Pull
the
two
side
casting
latches
fully
rear-
ward
(it
is
necessary
to
press
the
latch
handles
gently
away
from
the
center
of
the
instrument
to
unlock
them).
c.
When
latches
are
fully
extended
rearward,
the
5300A
and
plug-on
castings
should
be
separated
by
about
1/8-inch.
d.
Lift
the
5300A
gently
away
from
the
plug-on.
e.
Separate
5300A
Logic
Board
Assembly
from
5300A
casting
as
follows
(refer
to
Figure
5-1):
1.
Remove
retaining
screw
located
near
power
transformer.
2.
Press
rear,
plastic-nylon
retaining
clips
on
each
side
of
the
5300A
casting
and
lift
the
rear
of
the
Logic
Board
Assembly
to
release
it
from
the
casting.
3.
Press
front
plastic-nylon
retaining
clips
on
each
side
of
5300A
casting
and
lift
the
front
of
the
Logic
Board
Assembly
to
release
it
from
the
casting.
f.
Mate
the
5300A
Logic
Board
Assembly
to
the
plug-on
used
and
reapply
ac
power.
5-7.
PERIODIC
MAINTENANCE
5-8.
To
determine
if
the
5300A
is
operating
within
specifications,
perform
the
In-Cabinet
Performance
Checks
listed
in
the
documentation
for
the
specific
plug-on
used
and
the
troubleshooting
methods
and
procedures
listed
in
Paragraph
5-13.
5-9.
MAINTENANCE
AND
REPAIR
A1U3,
A1U4,
A1U5
are
large-scale
MOS
inte-
grated
circuits
whose
inputs
are
susceptible
to
damage
from
high
voltage
and
static
charges.
Particular
care
should
be
taken
to
avoid
exces-
sive
capacitive
loading
with
probes
or
when
handling
under
conditions
where
_
static
charges
can
build
up.
5-10.
BOARD
REMOVAL.
When
removing
the
printed
circuit
board
for
replacement,
repair,
or
servicing,
always
remove
ac
power
and
separate
the
board
from
the
casting
using
steps
a
to
e
of
Para-
graph
5-6.
5-11.
COMPONENT
REPLACEMENT.
When
re-
placing
a
circuit
board
component
use
a
low
heat
soldering
iron.
Heat
must
be
used
sparingly
as
damage
to
the
circuit
foif
may
result.
Mounting
holes
5-2
may
be
cleaned
out
with
a
toothpick
while
heat
is
applied.
Connection
should
be
cleaned
with
a
clean-
ing
solution
after
component
removal
and
replacement.
5-12.
INTEGRATED
CIRCUIT
REPLACEMENT.
Two
methods
are
recommended
for
removing
inte-
grated
circuits
(with
exception
of
U1,
U2,
U3,
U4,
and
U5):
a.
Solder
Gobbler.
Solder
is
removed
from
board
by
a
soldering
iron
with
a
hollow
tip
connected
to
a
vacuum
source.
The
IC
is
removed
intact
so
it
may
be
reinstalled
if
diagnosis
is
wrong.
b.
Clip
Out.
This
method
is
used
when
an
IC
is
proven
defective.
Clip
leads
close
to
case,
apply
heat
and
remove
leads
with
long
nose
pliers.
Clean
board
holes
with
toothpick
and
cleaning
solution.
5-13.
INSTRUMENT
TROUBLESHOOTING
5-14.
GENERAL.
Trouble
isolation
can
best
be
ac-
complished
by
first
obtaining
all
possible
information
from
controls,
connectors,
and
indicators,
then
logi-
cally
using
this
information
to
locate
the
defective
component.
5-15.
MODULE
SUBSTITUTION.
Maintenance
pro-
cedures
in
the
5300A
may
be
simplified
by
isolating
the
problem
to
one
or
a
group
of
the
Integrated
Circuits
and
replacing
the
suspected
bad
IC’s
with
known
good
spares.
Here
is
a
recommended
list
of
spares
which
will
assist
you
in
quickly
troubleshooting
and
servicing
the
5300A:
HP Part No.
U1,
LSI.
LED
Scanner
1820-1060
(Light-Emitting-Diode)
U2,
L.S.1.
Character
Generator
1820-0571
U3,
MOS
6-Decade
Counter
1820-0634
U4,
MOS
Time
Base
1820-0633
U5,
L.S.I.
Control
1820-0632
A2
Power
Supply
Regu-
05300-60003
lator
Board
A1Q3
Power
Transistor
1854-0487
A1A1
DS1-DS6
Light
Emitting
Diodes
1990-0325
and
DS8
5-16.
TROUBLESHOOTING.
Three
methods
of
troubleshooting
are
available.
There
are:
a.
5300A
mated
to
the
plug-on
in
use.
Tests
located
in
Paragraph
5-20
and
Figures
5-2
and
5-3A
(steps
6
to
13)
can
be
performed
with
plug-on
mated
to
the
mainframe.
Additional
tests
can
be
performed
with
a
plug-on,
using
performance
and
maintenance
checks
in
the
plug-on
section.
b.
Diagnostic
Test
Cards.
Test
Cards
05300-
20011,
20012,
20013,
and
20014,
and
Diagnostic
Inter-
face
card
05300-60004
are
factory
available
cards
which
have
fixed
programs
used
in
exercising
the