HP 339A - Page 114

i^Mof
8
MANUAL
CHANGES
Model 339A
CHANGE
NO.
IS (applies
t« ail
instruments)
(effective an
serial
number
1730A00916
and aboval.
Page
6-6.
Table
8-3.
Change
the
part
number
and value of A3C1
32*
from
0160-2249,
4.7pF
to
the
following
list:
0160-2251
0160-2253
0160-2254
0160-2255
0160-2256
0160-2257
0160-2259
0160-2261
CAPACITOR-FXD
5.6pF
CAPACITOR-FXD
6.8pF
CAPACITOR-FXD
7.5pF
CAPACITOR-FXD
8.2pF
CAPACITOR-FXD
9.1pF
CAPACITOR-FXD
lOpF
CAPACITOR-FXD 1
2pF
CAPACITOR-FXD
1
5pF
Note
that the
value most
often
installed by
the factory
is lOpF.
This
change
is to
prevent
U101
from oscillating.
Page
8-1318-14.
Fignra
8-13. Change
the
schematic value
of Cl
32*
from 4.7pF
to
lOpF.
two gates
of Q1
00
should
be
connected to
pin
3
of
U1
00
in-
of
pin
2
as shown.
On the
schematic
break
tne line
between
t^egates
common
point and
the
feedback
loop of
U
1 00
and
draw
a
new line
straight
down to TP101
and
pin
3
of
U100.
Source-follower
Q100 keeps
the
voltage across
tne
input
protec-
tion diodes
constant.
Prior to
this
change the bootstrap
voltage
came
from the
feedback
network
of
U100
(pm
2)
rather
than
the
input signal,
causing
distortion at
higher
frequencies due
to
the
delay
in the feedback
signal.
CHANGE
NO. IS
(effective os earial
numbers 1730A00916
to 1730A02436).
Pege
6-8, Tsble
8-3.
Add
A3R60,
part
number 2100-3210,
value
1
0K0.
Paga
8-1518-18,
Figere
8-14.
Add
R60.
a
10k variable
resistor,
in
series
with A3E1
photoresistor.
(applies
te ell
inetreaientxl
(effective oe
serial
number 1730A02436
sad above)
Page
6-8.
Tsble
S-3.
Delete all
information
on A3R60.
Page
8-1518-16, Figere
8-14.
Remove
R60
and replace
with
a
wire
nper.
s
was
installed to
insure that
phase
control (which runs
the er-
ror lights)
would
not pull down to as
low a
bridge resistance
as
the
amplitude
control
and the
LO
frequency
lamp always
lights to
signal
when
the frequency
is
too
low It
was
later
removed
because
it
was
seldom used.
CHANGE
NO. 17
(applies to ail
iaatreeteats) (effective on
serial
numbers
1730A00850
te
1730A0085B
aad
1730A00986
and aboval.
Page
8-6, Table
6-3.
Add
leference
designator A3C28,
part
number
0160-2264. value 20pF.
Paga 6-8,
Table
6-3. Change the part
number and value
for
the
following reference designators:
A3R42 from 0698-3161
38.3k«
to
0757-0454 33. 2kQ
A3R43 from 0757-0451
24.3kf2 to 0698-31
58
23. 7k«
A3R48 from
0757-0446 1
5k«
to
0757-0452 27.4kfl
A3R49
from
0698-3152
3.48k« to
0757-0439
6.81kfl
Page 8-1518-16.
Figera
8-14.
Change the
schematic values
of the
resistors
above
as
shown. Add
C28,
value
20pF in parallel
with
R49.
•
i addition of
C28
and
the change in
value
of
R49 is
to
eliminate
MHz oscillation
in
A3U3.
The other resistor changes
allow the
photocells A3E1
and A3E2
to
pull the
notch in
through a
wider
range
of
frequencies.
Prior
to
this change,
photocells which
met
specifications but
were at
the
limits
would
not
work.
CHANGE
NO. 18
(applies te ail
iestrumants)
(effective
on serial
nember
1730A014BB
and above)
Page
8-12.
Table
8-3. Change
the
part
number of
reference
designator
F2
from 211
0-0384 to
2 1 1
0-06
1
2.
The
old fuse
caused
3rd
order
harmonic
distortion at
low
frequen-
cies due
to its
thermal
properties.
CHAN6E
NO. 19
(effective
on on
serial
nembers 1 730A01
756
to 2025A03427)
Page
8-6. Table
8-3.
Change
the
part
number
and value
of
A3C1 00
from
0160-2251,
5.6pF
to
0140-0209,
5pF
Page
8-13/8-14, Figaro
8-13. Change
the
value
of
Cl 00
from 5.6pF
to
5pF
This
change
eliminates
the
possibility
of
a
short
from 10V
to
ground.
(applies
to all
instruments)
[affective on
serial
number
202SA03427
and
aboval
Page
6-8. Table
8-3.
Change
the part
number
and value
of A3C100
from
0140-0209,
5pF to
0160-2244, 3pF.
Page
8-13/8-14. Figure
8-13. Change
the value
of Cl 00
from 5pF to
3pF.
CHANGE
NO. 20
(applies to all
instruments)
(affective
on
serial number
2025A02226
and aboval
Page
6-6. Table
8-3. Change
the
part
number and
value of
the
follow
ing
reference
designators as
shown
below:
A3C1
15
from
0160-2263
1
8pF
to
0140-0190
39pF
A3C1
16
from
0140-0195 1
30pF to
0160-0134 220pF
Page
8-1318-14,
Figere
8-13. Change
the value
of Cl
'
5
from 1
8pF
to
39pF and
of
Cl
1
6
from 1 30pF to
220pF
Page
6-5,
Table
8-3.
Add
A2C5C'
and
A2C51
whose
part
numbers
are
0160-4571 and
values
are
1
uF
Paga
6-6,
Table
8-3.
Add
reference
designators
A2R50 and
A2R51
whose part
numbers
are
0757-0401 and
values are
1000.