DYNACO FM-5 User Manual

PROTESSIONAL
SERVICE
ATIGNMENT
(FOR
QUALIFIED
PERSONNEL
WITH
THE PROPER
LQUIPMENT
ONLY)
There is
no
provision
for
any home
alignment
of the
FM-s,
and
under
no
circumstances
should
any
adjust-
ments
be made
without
the
following
service
equipment:
1.
Sound Technology
10O0A
FM
alignment
generator,
or
the equivalent,
such
as
a Measurements
Corporation
Model
88 or 210,4.
generator,
plus
a suitable
multiplex
generator
with
adjustable
pilot
level,
and
an
accurate
67
kHz
oscillator.
2. Oscilloscope-Hewlett
Packard
130C or
equivalent
with
its Diode
Probe
and a 10:1
Probe.
3. AC voltmeter
with rnrs
scale.
4. DC voltmeter,
with
0.5
volt
or
less
full
scale;
l0 megohms
input
impedance.
5. Intermodulation
Analyzer.
Operate
both the
tuner
and
the instruments
for
at
least
20 minutes
prior
to
alignment"
lF Alignment
Locirte
a dial settirrg
between
slations.
Switr:h the tuner
to NIONO,
Dynatune
OIrF,
and
maximum
volurne.
Tune
t.he
gerrerator
to the
same
frequency
with
2O0
kllz
devia-
tion
and :r
3fiX)
1r.v
output. Cotrnect
the
diode
probe
to
the scope
vertical
input,
with
a sensitivity
of
l0
mv/cm.
Set the scope's
horizontal
extcrnal
sensitivity
for
I v/cm,
with
the swccl)
I
"external"
or "horizontal"
)
output
of the
generalor
connectr:d
to
the horizontal
input.
'I'he
rliode
probe
connected
to Tp
1 of
pCl
15 *;11
show
tuning
:rs
a bandJrass
curve.
()enter
the
curve
on ther
scoJre
clisJrlay
with
the
tuning
knob.
'I'he
IF
secondarv,
accessible
tlrrotrgh
a
hole
in
the front
panr:l,
is
the only
adjustment
on
the front
end.
Seek
the
best
combination
of
s-ymntetr.y
and
lrnrplitude.
Detector
Redrrqr
lhe
swt't'1r
tct
75 klfz,
but be
cart'ful not
to touclr
ther
tuning
of eithcr
the
generator
or the I,'M-ir.
('onnerct
thc
I)C voltrrretcr
(
on its nrost
sensitivc scale
)
to
thc
tuner
chassis
and
to t'.velet
$4
on I,(l-25.
Adjtrst the
st'conrl:rrv
(
top.t
of ther
dgfeglor
transformer
T
1 for zero.
I)isconnect
the
diode
probe.
Switch the
gcnerator
to external
modu-
lation
and
connect
IM
an:rlyzer
to
it. I'he
IM
sign:rl
should
be in
:r 1:
I ratio
to
allow
for de-emphitsir;.
AdJust
the
IM
anal.yzt'r
level
for 100fti
modulation
as
indicaterl
on
the
modulation
nteter.
(lonnect
the
tuner
output
to the
IM
analyzer.
Adjust
the
primary
(
bottom
)
of the
detector
transforrner
for rninimum
IM. Ilemove
IM
analvzer.
Audio
level
Maintain
3(XX)
1rv
signal level
and switch
to
400
Hz
modulation.
Adjust
trimpot
P 4 on
PC-25 for
2
volls
audio
output
from
tuner
with
the volunre
control
fullv
up.
Muting
Threshold
Switch to
MU'|E,
attenuate
the
generator
output
to
8
pv
(assuming
the
use of
a 2:1
balun.),
and
adjust trimpot
p'b2
on
PC-26
until the
audio
just
rnutes
off.
Adjust
trimpot
P
52 until
audio
just
comes
on
ractually
4
t.v)
.
Dynatune
Return tl're
generator
to
3000
pv.
Connect
the
DC
probe
to
eyelet
#
-l
on I'(l-25.
Retune
for zero
if necessary.
Then
switch
the rnute
switch
to
DYNATUNE.
If
the zero incli-
cation
changesat
all,
adjust trimpot
P 3 on PC-25 for
zero.
67 kHz
Filtering
F
rom
an external oscillator
connect
an
accurate
67
kHz
source to
the external modulation
input of
the FM
genera-
tor.
(lonnect
the l0:l
probe
to
the negative
side
rthe
top
end) of O
51.
While observing
the
67 kHz on
the scope,
adjust filter
FL
52
for minirnunr
arnplitude.
Multiplex
Switch to
STEREO.
(lonnect
the
stereo
generator
to the
external input
of the FM
generator.
(lonnect
the 10:1
1;robe
to the
vertical
input of
lhe scope,
and set
the
internal
sweep
to
approximatcly
2 milliserxrnds/cnr.
(lonnect
the
probe
to
eyelet
f
ll on
l'(l
26.
Pcak
both ttre 19kHz
coils
L
52 and L
53 for nr:tximurn
vertical
deflection.
Go back
and forth.
Retluce the
pilot
level on
the
nrrrltipk:x
gcnerator
to 5o1,.
Adjust trimJxrt
P
51
trntil
the
S'I'FIREO light
goes
out.
Thcn
adjust trirnyrot
I' irl r.rntil
the
ST'EREO
light
just
comes
on.
'l'he
S'I'FIRFIO
lighl should
conle on
at
l:o,,,,
of
the
tot:rl
rrurriulation.
Ilcturn
ltilot
lcvel
:rt
generator
to
tU.L.
Move the
probt'
to evelct
#12
on P(l,26and
adjust
t,he il8 kHz
coil [,
54 for
rn:rxirnurn
vcrtical
deflection.
Rerrrove
probc.
With I kHz rnorlulation
on the left
channel
onl.y, observe
the right
ch:rnnel
output
lnd
acljust first thc il8
kHz
coil
L
54 nncl then
the l9 kHz
coil L
53
for nrinirnurn
indication
(
nraxinrurn
scparation
)
.
(lorrrpare
left
and right separation.
Switch to l0
kHz rnodulation
orr
the leftch:rnnel
and
adjust
filter IrL
5l for rninirnurtr
indic:rtion
(
rnaxinrurn
sr:o:rration
).
Meter Adjustment
Switch to MONO
and dccrease
F M
generator
output
to
10
p.v.
Set trimpot
P 1
on
PC-25 for
251( meter
deflection.
Increase
the
I.'M output
to 110,000
1,v.
Set
trinrpot
I,2
for
full
scale
meter
deflt'ctiorr-
ServiceNote:'fheTUNEDindicatorlarnpisapartof
thernrrtingcircuit.
If itis
shortecl
,theal6iowill
remainnrut.6,cve.
on
a station.
Switching
the
muting ofi
will
enable
signal
reception
until the
larlp
is replaced.
If the lalrp
is
op.ri, the
muting
circuit
will
not
work
and there
will
be noise
between
stations
in
all switch
positions,
ZU

DYNACO FM-5 Specifications

General

Brand	DYNACO
Model	FM-5
Category	Tuner
Language	English