Removing The Front Panel, Panel Meters - HP 3575A Manual

Section V GENEBAL SERVICING
IN FO
BMATIO
N
Model 3575
A
c.
Being careful
to
avoid straining cable W5
which
runs
fronr A3 to
A5
across
the top
of
A6. renlove
A6 by pulling
upwud on
1he
labs
at thc
cnds
of
the A6 top
cover.
d.
Input
cable
W7
is
long
enough
to
allow A6
to
be
rrrourtcd
on the
ll-pi11 PC extender
(hp-
5060-5989)
supplicd
with thc instrument.
lf
A6
is
to
be placed
on
the
extender,
first install thc
cxtcnder
in tile A6
socket
(route
W5 arouml the
extender). Then placc 46 on the
extender
and
rccofirecl input
cable. W7.
5-61.
Removal
ol
Assemblies
A8 through A11 and A14.
a.
Rcmove
thc Retainer Strap (MP
-15,
Figure
6- I
).
b.
Renlove
thc board
by lilting
the extractors
at
the
ends
of
thc board. No[e
tllat
the extractors are
color
coded
to
iderltify the
asselrbly number.
The extractor
colors
rnatch
tl1c
corresponding
guides on thc main frame.
5-62. lnterface Substitution Board,
A164. The IIll.rt'acc
SLrbstilution Boerd.
Al6-,\.
is
r
PC
card
thal
is
usecl
lo
nreke
connections between
lhe
lionl
partel controls aJld
the
f'unctioo Swiiching
Assembly
(A8)
in
tlte
absencc
ol
lire
Interface
Assenrbly,
Al68
(A168 is in
Options
001
and
00-1). When
instaiiing
Al6A.
be sure
thlt
thc
side ntarked
"FACI. I
HIS SIDL
TOWARD
IrlloNl "
is
facirg the
fionl
prnel.
Reversing
Al6A will nol
danlage
the
instrurrent
but
will
cause
the
front plnel
coDtrols
1()
be
inoperativc.
5-63. lnterJace Assembly
(A16B
Bemoval.
Options
002.
003)
a.
Remove
the two
screws
that
fasten
the
[ntcrface
connector to thc
rear panel (large Phitlips hcad
screws).
b.
Whilc supportinB A16B
with
onc hand. unplug
A1!.)
from A16Il by pulling
outward on the
hterfacc
conncctor.
c.
Renrove
the A16B board
by lifting the extractors
at
thc
ends
of
the board.
d.
For troubleshor)ting. plaoc
Al6B on
the
ll-pin
PC
Extender
supplied
with the instrunlent Plug
Al9
into A16ll
if remote
connections
arc
rcquircd.
5-64.
Removing
the Front
Panel, Panel Meters and A12,
Rclcr
to the procedure oLrtlincd
in
Figure
5-5.
NOTE
F'or panel
ntc
t
crfittt cr<trutt:t
t
boartl
a.,tttbittu-
t
)
s
itt edrlier it$tnotrcttts, obtuin
Sen'icc
Xotc
-1575A-4,
"Origital
CortJigurutiLtrt
oJ
patrcl
ntetu a
Ll
literi)ntrcct
Bourds".
liont
.vour
-hp-
Sales
ontl
St'r'tice
Ollict'.
5-65. Component Beplacement.
5-6(r. When
replaciDg
conrponetlts
irt tlle
3575A.
observc
thc
gencral
qLridelines
listcd
in
Paragraph
5-69.
In
additon.
note thc
lollowing:
a.
Thc reed relays
on the hearrrplifier
Assemblics.
Al
and A2,
are
of
the
plug-in type.
To removc
a
reed
relay.
use
a pair of
long-nosed
pliers and gently
lift
each end
of
the
relay
until
it
is
uuplugged.
5-16
b.
To
remove
the Hybrid Log Amplifiers.
A3/A.1
lcl.
proceed
as
follorvs:
l)
Rerlove
the screw
that
fastens
the
[Cl
heat
sink
to
the
A3/A.1
top
cover.
1)
Renove the
two
nuts locatcd
dircctly
below
ICI
on the circuit
side
of
the board.
-l
1
Carclully unplug lC
I
fronr its
socket.
c.
\Vhe.r
rcplacing
transistors
and lC's, note the
lead
conliguratior) and positiorr
of
thc defective
cornporent
and
orient the
replaoerlent conlponerll in the
samc
manner
as
the original, Dots are provided
on the
PC boards
to
sl]ow
thc
orientation
of
IC's. For IC's
in
the
8-pirl
ciroular
packagc,
the
dot
indicates
thc tab (pin 8) position. For lC's
in the dual-in-line pacloge,
the dot
ildicates pin
1.
d,
Dots are provided
on thc
PC boards
to
show the
orientation
of
electrolytic capacitors
and
diodes.
l-or
electrolytic
capacitors,
the
dot
indicates
the positivc
lead.
For diodes. thc
dot
indicates the cathode lead.
5-67.
Servicing Etched Circuit
Boards.
5-68.
The Standard Model .1575A contailrs 19
pLinted-
circuit
(PC)
assenrblies.
Thc
ip-
part
nunrber
is
printccl
on
each asscmbly
for
identificati{)n. Identical
assemblics such
as
Al /Al.
,4.3/A,t
altd A9/A
l0
arc
ilterchangeable and
have
idcnrical
part
Iunrbcrs. Refer
to
Sectiorl
Vl
for
parts
replacernent and -hp- part runlber infornration.
5-69. The printcd-circuit
boards
in
the 1575A
rre ol
thc
plated throush type.
The
e'lcctricll conleclion
between
two
sides
of
a board
is made
by
a
layer
of
rnetal
plated tfuough
the colnporlent hole. When
servioing
prirlted-circuit
boards,
observe
the
following guidelines:
a.
Use
a low'heat
(15
to
30 watts) small-tip
soldering
iron, and small diunreter rosin-core soldct.
b.
Remove
coirporcnts and
clean component
holes
usirg
a
dcsoldcring
tool.
c.
Do not
overhcat the
PC
connections Gads).
d.
To
replacc somponerts, shape new leads and insert
them
in
lead holes.
Reheat
corlnections and apply a
small
anount
of
solder as
requfed
to
insure a
good
electrical
connection.
e,
Clean
excessive
flux lron
the con[ection
and
ad-
joinirg
area.
5-70.
Cleaning
the Display
Window.
5-71.
Wjren cleaning the
Display
\Vindow. du not
use harsh
chemicals
or
abrasives. Use a
soft cloth
alons
$ith
clear
\latcr
or
a
dilLlted
$indow
clearler.