HP 3400A Service Manual

Maintenance
d.
To
replace
components,
shape
new
leads
and
insert
them
in
holes.
Reheat
with
iron
and
add
solder
as
required
to
insure
a
good
electrical
connection.
e.
Clean
excess
flux
from
the
connection
and
adjoining
area.
5-43.
AG
ASSEMBLY
(03400-66512)
RETROFIT
PROCEDURE
5-44.
The
following
procedure
can
be
used
to
retrofit
older
3400A’s
that
have
the
old
A6é
Assembly
(-hp-
Part
Number:
03400-66508)
with
the
presently
available
A6é
Assembly
(-hp-
Part
Number:
03400-66512).
Since
modifications
to
the
A7
Assembly
(Power
Supply)
and
to
other
associated
components
of
the
A6
Assembly
are
required,
you
should
obtain
a
3400A
manual
that
has
the
schematics
(Figures
6-3
and
6-4)
for
the
old
A6
and
A7
Assemblies.
(A
manual
with
-hp-
Part
Number
03400-90008
or
lower
is
a
good
choice.)
Do
the
following:
a.
Turn
the
3400A
off
and
disconnect
it
from
the
ac
power
source.
~
b.
Refer
to
Figure
6-3
(schematic
of
the
old
A6
Assembly),
and
locate
and
remove
R3,
R8,
R9,
and
R10
from
the
instrument.
These
parts
and
parts
in
the
next
step
are
located
next
to
the
A6
Assembly
connector.
c.
Refer
to
Figure
6-3
again
and
locate
resistor
R4.
Connect
and
solder
both
legs
of
R4
together,
or
connect
pin
10
of
the
A6
Assembly
connector
to
the
CLR
line
of
thermocouple
TC402.
d.
Refer
to
Figure
6-4
(schematic
of
the
old
A7
Assembly)
and
locate
C711,
C712,
CR718,
CR719,
R701, R702,
R712,
R713,
and
Q706
on
the
A7
Assembly.
Then
remove
the
com-
ponents
from
the
assembly.
:
e.
Remove
the
old
A6
Assembly
(03400-66508)
and
replace
it
with
the
new
A6
Assembly
(03400-66512).
f.
Connect
the
3400A
to
the
ac
power
source
and
turn
it
on.
After
the
recommended
warm-
up,
calibrate
the
instrument
using
the
calibration
procedure
in
paragraph
5-15.
NOTE
After
calibrating
the
3400A,
the
instrument
may
display
a
small
offset
with
0
V
inputs.
This
is
normal
and
the
3400A
should
be
ful-
ly
accurate
from
1/10
scale
to
full
scale.
Model 3400A

HP 3400A Specifications

General

Brand	HP
Model	3400A
Category	Measuring Instruments
Language	English