Table of Contents
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the
pr
og
r
a
m
me
d
fre
qu
ency (fo
r
exa
mp
le . 10.420 MHz
i
n
stea
d
of 420
kHz),
a
nd
t
h
e TT
L
signal at
p
in 5 of mo
du
le
ΜΣΟ
W
-8 ί5 co
r
rect, t
h
e switc
h
is not wo
rk
ing, a
nd
t
h
e
pr
o
b
le
m
lies i
n
t
h
e
M
lO
W
-8.
It t
h
e i
n
st
r
ume
n
t o
p
e
r
ates properly fro
m
1 to 999 MHz,
bu
t not a
b
ove 1 MHz, check
f
or t
h
e TT
L
signal at p i
n
5 of
mo
d u
le Μ 10W-8. If it is correct, t
h
e
pr
o
b
lem lies In
t
h
e
Μ 10Ν-8 .
If t
h
e R
F
o
u
t
pu
t level f
r
o
m
I to 999 kHz is too low, and
cannot
b
e cor
r
ecte
d b
y recaii
b
retion, t
h
e
p
ro
b
le
m
lies i
n
eit
h
er t
h
e M1 15 o
r
α co
nn
ecti
n
g cable .
M
OD
UL
ATIO
N
T
R
O
UBLE
S
- Th
e
M
o
du
latio
n B
oar
d
(C316-2)
is t
h
e most common ca
u
se of mo
du
latio
n
p
ro
b
lems,
p
artic
u
larly w
h
e
n
t
h
e mo
du
lating signal is lost .
Non-linear am
p
lit
ud
e modulation α( higher-audio
f
re-
q
u
encies f
r
o
m
an external so
ur
ce may be ca
u
se
d
b
y t
h
e
Μ 10
W
-6/8 O
u
t
pu
t Amplifier.
Set t
h
e front-panel co
n
trols α 5 follo
w
s to
d
eter
m
ine
t
h
e
pr
ese
n
ce o
f
mo
d
ulati
n
g signal ;
FRE
D
VERN
I
ER
CA
L
M
OD
UL
ATIO
N M
OD
E
AM
M
OD
UL
ATIO
N FRE
D
400 Hr
M
OD
U
LATIO
N
FM/AM
maxi
mu
m
O
U
T
PU
T
VERN
I
ER
Fu
ll εω
O
U
T
P
UT Ste
p
Atte
n
uator
0
d
ate
Co
n
nect t
h
e oscilloscope ve
r
tical i
npu
t to
t h
e
r
ear-
p
a
n
el
MOO ΤΡ . T
h
e sco
p
e s
h
o
u
l
d
d
isplay α 10
Vpp
sine wave at α
f
r
e
q
ue
n
cy of 400 Hz (2 .5 msac
p
erio
d
) . Set t
h
e MODU-
LATION
FRE
D switc
h
to 1
kH
z. T
h
e scope
d
is
p
lay s
h
o
u
l
d
b
e α 10
Vpp
sine wave wit
h
α
p
e
r
io
d
of 1 msec. If t
h
e 10
V
sig
n
als a
r
e n ot obtai
n
e
d
, c
h
ec
k
fo
r
+7,3
V
on pi
n
Β. +18
V
on pi
n
2, a
nd
-18
V
on pin 2 of t
h
e C316-2
M
o
du
lation
B
oar
d
. If t
h
e DC voltages a
r
e normal,
t
h
e
M
o
d
ulatio
n
Board
is
d
e
f
ective .
AM T
R
O
UBLE
S
-
Con
n
ect t
h
e sco
p
e vertical in
p
ut to pin
3 of t
h
e C316 .2
M
o
du
lation Board and c
h
ec
k
fo
r
α 10
Vpp
5- 1 0
sine wave ; t
h
en, con
n
ect t
h
e scope vertical input to
p
i
n
4 of
M
eter Board 0315 and again check for α 10
V
sine wave .
P resence of t
h
e si
n
e
wave
at
t h
is
p
oi
n
t in
d
icates
p
ro
p
e
r
operation of the. Modulation
B
oa
rd a nd
its wi
r
i
n
g.
Connect the sco
p
e vertical input to pi
n
2 of
M
eter Βηα rλ
C315 and check
f
or α si
n
e wave havi
n
g an αρςιιοκί mαι e
amplitude of 1 .75
Vp
p. If the 1 .75
V
signal is not present,
c
h
ec
k
for +18
V
on
p
i
n
6 a
nd
-18
V
on pin 5 of the Meter
B
oa
r
d. Ι Γ
t
h
e OC voltages a
r
e no
r
mal,
M
ete
r B
oar
d
C315 is
d
efective or α wire is disco
nn
ecte
d
from Atten
u
ato
r
switc
h
St .
C
h
ec
k f
o
r
α 1 .75
Vpp
sine wave an pin 15 of module
Μ 10W-618 . If t
h
e sine wave is normal at
t
h
is
p
oint,
bu
t
a
mp
lit
ud
e mo
du
lation is a
b
nor
m
al, mo
du
le
M
IO
W
-6/8 is
d
e
f
ective .
FM
1 RO
UBLE
S
-
Set t
h
e
M
OD
UL
ATIO
N M
OD
E
to
FM
x10 an
d
c
h
ec
k
for α 10
Vpp
si
n
e wave on pi
n
6 ο 1
M
o
d u
latio
n B
oar
d
C316-2 ; t
h
e
n
, co
nn
ect t
h
e scope ve
r
tical
input 1ο pi
n
16 of mo
du
le Μ 29-2 a
nd
again c
h
ec
k
fo
r
α 10
V
sine wave . Α 400 Hz or 1
kH
z 10
V
si
n
e wave at
th
is
p
oi
n
t indicates proper operation of t
h
e
M
o
du
latio
n B
oar
d
and its wi
r
ing.
R
e
m
ove t
h
e
RF
ca
b
le fro
m
t
h
e to
p
of mo
du
le M29-2, and
c
h
ec
k
for α 1
Vpp
1 .8-2 .1 MHz signal at this con
n
ector.
If t
h
is signal is not
pr
ese
n
t, c
h
ec
k
fo
r
+1 θ
V
on pin 3 and
-18
V
on
p
in 4 of m o
d
ule Μ 29-2 . Ι 1
t h
e DC voltages are
normal,
FM
problems
a r
e ca
u
se
d b
y α
d
efective mo
d
ule
Μ29-2 If the 1 .92 .1 MHz sig
n
al is
pr
ese
n
t at t
h
e Μ 29-2
co
nn
ecto
r
,
FM p
ro
b
le
m
s a
r
e probably ca
u
se
d b
y α
d
efective
Μ33-2 m o
d
ule .
5.41
ASS
EMBL
Y R
EP
LAC
EMEN
T
Wh
ile in many cases the inst
ru
me
n
t will wo
rk
satisfactorily
after sim
p
ly re
p
lacing α
d
efective asse
mb
ly, to maintain
t
h
e. high accu
r
acy of w
h
ic
h
t
h
e unit is ca
p
a
b
le, asse
mb
ly
re
p
lacement s
h
o
u
l
d
be followe
d b
y calibration of t
h
e
affecte
d
circuits . Ta
b
le 5-3 lists eac
h
assem
b
ly a
nd t h
e
a
dju
st
m
e
n
t nee
d
e
d
.
ASS
EMBL
Y
AD
JU
ST
M EN
T
RE
Q
U
I
RE
D
RE
P
L
AC
E
D
IS" in
d
icate
d
actions in Calibration Procedure)
Ta
b
le 5-3 .
Asse
mb
ly
Μ9ω Swee
p
Oscillator
Reset
P h
ase-
L
oc
k
e
d
Loops 3 and 4 (5 .31 an
d
53S)
R
e
p
lace
m
e
n
t
M
10
W
6r8 Out
p
ut Am
p
iι
f
ier
R
ecalibrate C315
M
eter
B
oar
d
(5 .3 .101
Cali
b
ratio
n
Μ 172 Swee
p
Drive/DAC
R
eset Phase-
L
oc
k
e
d L
oo
p
4 15 .3.3)
Μ29-2
FM R
eference
Reset
Ph
ase-Loc
k
e
d L
oo
p
5 (5 .3.91
Μ30-1 Crystal
R
eference
Adjust Crystal
F
re
q
uency (5 .3.4 an
d
53 .12)
Μ 31 Α
kH
z Steps
None re
q
uired
Μ32 Α MHz Steps
A
dj
ust
Ph
os σ-
L
oc
k
e
d L
oo
p
2 15 .3.61
Μ33-2
N
arrow Osc. Lark
Adjust
Ph
ase.
L
oc
k
e
d
Loop 3 15 .3.71
Μ34
W
i
d
e Osc,
L
oc
k
Set Μ34 pin 14 for +1 .0
V
OC 15 .3 .81
MI 15
Down Cοπνοη er
A
d
just Gain Calibration 15 .3 .111
C315 Meter Boar
d
Adjust
M
eter Board Calibration (5 .3.10)
C316-2 Modulation
B
oard
A
dj
ust
Ph
ase-
L
oc
k
e
d
two 5 15.39)
D
P
S2A Power Supply
Ad
j
ust ±18
V
an
d
chec
k
7.3
V
15 .3 .1-5 .3 .31
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