HP 339A - Page 113

dfeel
339A
MANUAL
CHANGES
Page 3
of
8
CHANGE NO. 10
(applies
to aU
iastrumeats).
Pago
g-3,
TaWo
8-3.
Add
the
following
list of part
numbers
and
values to A1
C47*:
0160-0356
0160-2306
0160-0204
0160-0376
0140-0193
0140-0194
0140-0198
CAPACITOR-FXD
1 8pF
CAPACITOR-FXD
27pF
CAPACITOR-FXD
47pF
CAPACITOR-FXD
68pF
CAPACITOR-FXD
82pF
CAPACITOR-FXD
IIOpF
CAPACITOR-FXD
200pF
Note
that the
value
most
often
installed by the
factory
will
be
200pF.
The
other values
are
possible
alternatives.
Selection
of
this
value
will
optimize the
high
frequency
I
>
1 00kHz)
distortion.
Page
8-21/8-22. Figar#
8-17. Change
the value
listed
on the
schematic
for
C47*
from
510pF to
200pF.
CHANGE NO.
11
laffacthra
aa serial
numbers 1 730A01 1 82
ta 1 730A0
1 956).
*
6-9,
Table
8-3.
Add
A4C32*
and
the
following
list of
part
aers and
values:
0160-2248
0160-2249
0160-2250
0160-2251
0160-2252
CAPACITOR-FXD
4.3pF
CAPACITOR-FXD
4,7pF
CAPACITOR-FXD
5.
1
pF
CAPACITOR-FXD
5.6pF
CAPACITOR-FXD
6.2pF
Note that
the value
most
often
installed
by
the
factory
will
be
5.1pF.
The
other values
are
possible
alternatives.
Page
8-17, Figare
8-15.
Add
capacitor C32*
in
parallel with R2.
The
value
of
C32*
should be
listed as
5.1pF
This
addition
will provide
phase shift
at
1
1
0
kHz
which will
im-
prove the
fundamental
rejection at
that frequency.
(applies to
ell
iastraaiaaUI
(effective oe
serial
nambar 1730A01958
and
above)
The installed
value
for
C32*
is 6
2pF. Since
the above
list already
includes this value a
schematic
change is all that
is necessary
CHANGE
NO.
12
(applies
to
all
instruments)
B
(effective
on serial
number
1730A00598
and
above!.
Page 6-5. Table
8-3. Change
the part number
of A2C23
from
01
80-1 746
to 01
80-2944. The
new part is the
same value
but
has a
leakage
specification
of
0
05
uA maximum
(g)
14
VDC.
C23
is
used
to slow
the
response
time of the
rms
detector U5,
which consequently
slows
the
meter response
in the
NORMAL
mode.
In the
VU
mode
C23
is
switched out
of the circuit.
If the
dc
leakage
through
C23
exceeds 05uA a dc
voltage offset
occurs at
pin
4 of
U5
causing
an
erroneous meter
reading.
Page
8-7. Table
8-3. Change
the part number
and value
of A3C324
from 0180-0374, 1 OuF
to 01
80-0374,
15uF.
Page
8-2318-24. Figure
8-18. Change
the schematic
value
of
C324
from
1
0uF
to 1 5uF.
Raising
the value of this
capacitor
will lower the ac
impedance
of
the -15V
power supply
to
the A2 board.
This will
improve the
operation
of the
80
kHz
filter.
CHANGE NO. 13
(applies to
all instrumental
(affective on
Serial Number
1730AQ077S
and aboval.
be
6-3, Table
6-3.
Change
the part number and
value of A1C21
Im
0180-1745,
1.5uF to
0180-0197, 2.2uF.
Page
8-21/8-22. Figure
8-17.
Change the
schematic value
of
C2
1
from
1 .OuF to
2.2uF.
This change
reduces
the
1 0Hz
ripple
in the
amplitude
control
cir-
cuits.
A large
ripple
voltage at
TP4 can cause
CR4
to
turn
on
which
causes
harmonic
distortion.
Pigs
8-5,
Table
6-3.
Delete all
information
on A2C21
.
Page B-19/8-20.
Figure
8-16.
Delete C21
from the
schematic.
This part
has been
deleted
because
the
newer
rms
detectors
(A2U5) do
not
require
its
use.
(effective oa
serial
numbers
173QA0077B
to 2025A02646)
Page
8-4,
Table
6-3. Change
the
part
number
and
value
of A2C13
from
0160-2244,
3pF to
0160-2236,
IpF.
Page
8-19/8-20. Figure
8-18.
Change
the
schematic
value
of Cl
3
from
3pF to
1
pF.
This change
has
come
about
to
increase
the bandwidth
of A2U4.
The old
rms detector,
A2U5,
had a
peak
in the
response
at
1 1 0kHz
which
compensated
for the reduced
bandwidth of
A2U4.
The
new detectors
(marked
AD536AJ)
don't
have
this
peak
in
their
frequency
response.
(applies
to all
instruments)
leffsctiva
on serial
numbers 2025A02646
and
above)
P*ga
6-4. Toble
8-3. Delete
all
information
on
reference
designators
A2C1
1 and A2C1
3.
Page
8-19/8-20. Figure
8-16. Delete
schematic
symbols,
values,
and
designators
for
Cl
1
and Cl 3.
(effective
on
serial
numbers 1730A00778
to
2025A02226)
Page
8-6. Table
8-3. Change
the
part number
and
value
for A3C1
1 4
from
0160-0363,
620pF
to 0160-2209,
360pF.
Page
8-13/8-14.
Figure
8-13. Change
the
schematic
value
of Cl
14
from 620pF to
360pF.
(applies
to all
instruments!
(effective
on serial
number
2025A02226
and aboval
Page
8-6, Table
8-3. Change
the part
number
and
value
of
reference
designator
A3C114
from
0160-2209,
360
pF to
0160-0341,
640pF.
Page
8-13/8-14 Figure
8-1
3.
Change
the
schematic
value
of Cl
14
from
360pF to
640pF.
CHANGE
NO.
14 (applies
to all
instruments)
(effective
on serial
number 1730A00844
and
above).
Page
6-10.
Table
6-3. Change
the part
number
and
value for
A4R48
and
A4R52
from
0698-4435,
2.49k0
to
0698-3515,
5.9kl2.
Pipe
8-17,
Figure
8-15. Change
the
schematic
values
of R48
and
R52
from
2.49k«
to
5.9k«.
This
change
is
being done
to
decrease
the
lock-in
time
of the
notch.
Low
level
1 20Hz
line
signals could
beat with
the fun-
damental
when the 339
is
tuned to
100Hz causing "out
of
specification"
distortion
readings at
100Hz.