HP 5254C - MODEL 5254 A ASSEMBLY CHANGES

Model
5254C
Section
VII
Table
7-1,
A5
Video
Amplifier
Assembly
Make
the following
changes
in
parts
list
for
A5:
A5R32:
change
to
R FXD
2400
OHM, HP
PART NO.
0683-3925.
A5E1:
delete
CHANGE 2:
Figure
7-2
A5
Video
Amplifier
Assembly:
Make
the
following
changes:
A5R2:
change to:
R
FXD
100K
Table
7-1 A5
Video
Amplifier
Assembly:
Make
the
following
changes:
A5R2:
change
to:
R
FXD
100K,
HP
PART
NO.
0683-1045.
MP4:
change
to
HP
PART
NO.
MP5: change to
HP
PART
NO.
MP6: change to
HP
PART
NO.
MP7:
change
to
HP
PART
NO.
MP8 : change
to
HP PART NO.
MP12: change to
HP
PART NO.
05254-2029
05254-0007
05254-0004
05254-0003
05254-0002
05254-0001
7-20.
MULTIPLIER
AMPLIFIER
ASSEMBLY Al.
7-21.
The Multiplier
Amplifier
is similar
to that
used in
the
5254B. The main
difference is
that
A1R17
is
not used
and
A1R16
is
changed
to
10K ohms (a fac-
tory
selected
value,
typical
value
shown).
See
Fig-
ure
7-5.
7-22.
HARMONIC
GENERATOR
ASSEMBLY A2
AND
HARMONIC
SELECTOR
CAVITY.
7-23.
The Harmonic
Generator and
Harmonic
Selec-
tor
Cavity are
the same as
that
in
the
Model
5254B.
(See
Figure
7-5.
)
7-24.
MIXER
ASSEMBLY
A3.
7-25.
The
Mixer
Assembly is
the
same
as that
in
the
5254B.
(See
Figure
7-6.)
7-26.
FILTER
ASSEMBLY
A4.
7-27.
The
Filter
Assembly
is
the
same
as
that in
the
5254B. (See
Figure
7-6.)
7-28.
VIDEO
AMPLIFIER
A5.
7-29.
The
Video
Amplifier is
similar to
that
used
in
the
5254B.
(See
Figure
7-6.)
However,
trigger
cir-
cuit
A5Q13,
A5Q14,
and
A5Q15
has
been
eliminated.
The
output
signal
at
A5Q10
emitter
is
applied to
A5Q11 base.
A5Q11 is
a
buffer
amplifier
with
a re-
sistive
divider
output
providing
the
output
to
the
coun-
ter
and
the
external
output.
There is
sufficient
isola-
tion in
the
divider
network
to
prevent
the
signal
to
the
counter
from
being
affected
by
termination
at
the ex-
ternal
output.
7-30.
The
signal
for the
meter
amplifier
is
taken
from
A5Q10
emitter
and
applied
to
A5Q12
base.
Meter
amplifier
A5Q12 is
a
current
amplifier
driving
meter
rectifier
A5CR2.
A5R39
and
A5C22
provide
damping
for the
meter.
A5C19
adjusts
the
meter
amplifier
high
frequency
gain
to
make the
level
meter
read
at
red-green
border
when
converter
output is
more
than
the
minimum
100
mV
normally
required
at
the
counter
input.
*
Ferrite
bead
A5E1
was
added
to
A5Q12
emitter to
suppress oscillation caused
when
A5R32
was changed
for improved A5Q12
operation.
7-3