HP 3400A Service Manual

Model 3400A
f. Leads on new thermocouples must be shaped before inserting into PC board. During
the shaping process, hold leads between bending point and glass with long-nose pliers.
g.
Place
the
red
dots
on
the
thermocouples
face
down
on
the
A4
Video
Amplifier
Board.
If
one
of
the
thermocouples
has
an
additional
colored
dot
place
it
in
the
TC402
position.
h. Carefully insert new thermocouple leads and solder.
i.
Reverse
steps
e,
d,
c,
b.
Note:
the
violet
lead
goes
to
the
lower
of
the
two
top
connec-
tors
on
the
A4
board.
j.
After
thermocouple
replacements
perform
a
complete
adjustment
and
calibration
pro-
cedure
as
outlined
in Paragraph
5-15.
Table 5-7. Factory Selected Components
eee eee Pe
C205 Adjust low frequency (10 Hz) response. 100pF
(selected)
C302 Adjust high frequency (10 MHz) of Second Attenuator 12 pF 15 pF
on 0.001 V and 1 V ranges.
C304 Adjust high frequency (3 MHz to 10 MHz) of Second 24 pF 39 pF
Attenuator on 0.3 V and 300 V ranges.
C305 Adjust high frequency (10 MHz) of Second Attenuator
on 0.01 V and 10 V ranges.
moe pe a oe meee NOTE on schematic. 200 pF
—
Eee 9 [pala tenies ae voltage at collector of Q406 (with no signal in-
put) to 1.5V to 2.5V de.
5-40. SERVICING ETCHED CIRCUIT BOARDS
41.
The
-hp-
Model
3400A
has
five
etched
circuit
boards.
Use
caution
when
removing
them
to
avoid
damaging
mounted
components.
The
assembly
and
-hp-
Part
No.
are
silk
screened
on
the
interior
of
the
circuit
board
to
identify
it.
Refer
to
Section
VII
for
parts
replacement
and
-hp-
part
number
information.
5-42.
The
etched
circuit
boards
are
plated-through
type.
The
electrical
connection
between
sides
of
the
board
is
made
by
a
layer
of
metal
plated
through
the
component
holes.
When
working
on
these
boards,
observe
the following
general
rules:
a.
Use
a
low-heat
(25
to
50
watts)
small-tip
soldering
iron
and
a
smal!
diameter
rosin
core
solder.
b.
Circuit
components
can
be
removed
by
replacing
the
soldering
iron
on
the
component
lead
on
either
side
of
the
board
and
pulling
upon
lead.
If
a
component
is
obviously
dam-
aged,
clip
leads
as
close
to
component
as
possible
and
then
remove.
Excess
heat
can
cause
the
circuit
and
board
to
separate
or
cause
damage
to
the
component.
c. Component lead hole should be cleaned before inserting new lead.
Maintenance

HP 3400A Specifications

General

Brand	HP
Model	3400A
Category	Measuring Instruments
Language	English