Yamaha SY77 Service Manual page 43
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SY77
SY77
TEST
END
Press
lEXIT] to
end
the
test.
After pressing [EXIT] three things occur;
(1)
the following
display
will
appear,
(2)
the
sound
will
stop
and
(3)
the
SY77
will
wait
for
the
entry
of
a
test
number.
*
38:
Elfect.O
to
LI
Output
OfJ
39.
TEST
39:
IkHz
FM SOUND OUTPUT
[EFFECT
1
-
OUTPUT
LI]
TEST
i
t
39;
Ellect.l
to
LI
There
are
two
signal
paths
for
this test.
The
basic
signal
path
is
the
same
as
it
was
for
TEST
31
except
for
the
following:
SIGNAL
PATH
1
The
signal
from
the
PAN
1C
is
input
to
pin
2
(SIO terminal) of
the
LEF
(1)
tC
(IC232)
via pin
9
of
IC254.
The
signal
is
then output from
pin
4 (SOO
terminal) of the
LEF
(1
)
1C
to
pin
10
(SIO terminal)
of
the
LDSP
(1)
1C
{IC236).
The LDSP(I)
1C
outputs the
signal via pin
33
(SOO
terminal) to pin 2
(MIX2
terminal) of
MIX3
(1)
1C
(IC242). This
ultimately
produces
signal
output
from
OUTPUT
LI
and
OUTPUT
Rl.
SIGNAL PATH
2
The
signal
from
the
PAN
1C
is
input to
pin
2
(SIO terminal) of
the
LEF
(2)
1C
(IC233)
via pin
19
of
IC254.
The
signal
is
then output from
pin
4 (SOO
terminal) of
the
LEF
(2)
1C
to
pin
10
(SIO terminal)
of the
LDSP
(2)
1C
(IC237).
The
LDSP
(2)
1C
outputs the
signal via pin
33 (SOO
terminal) to pin
2
(MIX2
terminal) of
MIX3
(2)
1C
(IC243). This ultimately
produces
signal
output
from
OUTPUT
L2
and
OUTPUT
R2.
It
should be noted
that the
LEF
ICs
use
their
associated
DRAM
ICs
and
the
LDSP
ICs
use
their
associated
PSRAM
to
process the
signals
for this test.
ITEMS
TO CHECK
Insert
the appropriate 1/4"
phone
plug
into
OUTPUT
LI only
and
verify,
if
necessary, the frequency,
output
waveform,
output
level,
and
THD
of this
output
using the previously specified test equip-
ment
(refer
to
TEST
31
1
.
The volume
control
must
be
set
at
maximum
for this test.
While sounding,
the
LCD
will
display the following
message:
*
3S:
Efiect.l
to
Li
Output
On
The
specifications
for this test
are as follows:
OUTPUT
LI
:
1kHz,
sine
wave,
distortion
0.3%
or
less,
+
1
1.0dB±2dB
(10k
ohm
load)
TEST
END
Press
(EXIT) to
end
the
test.
After pressing
(EXIT! three things occur;
(1)
the following
display
will
appear,
(21
the
sound
will
stop
and
(3)
the
SY77
will
wait
for
the entry
of
a test
number.
»
39:
Eliect^l
to
Li
Output
OH
40.
TEST
40:
1kHz
FM SOUND OUTPUT
(EFFECT
2-OUTPUT
LI}
TEST
>
40:
EHuct-J
to
LI
There
are
two
signal
paths
for this test.
The
basic
signal
path
is
the
same
as
it
was
for
TEST
31
except
for
the
following:
SIGNAL PATH
1
The
signal
from
the
PAN
1C
is
input to
pin
2
ISIO terminal) of
the
LEF
(2)
1C
(IC233)
via pin
19
of
IC254.
The
signal
is
then output
from
pin
4 (SOO
terminal)
of the
LEF
(2) 1C
to
pin
11
(SI1
terminal)
of
the
LDSP
(11
1C
(IC236I.
The LDSP
(1)
1C
outputs the
signal via pin
33
(SOO
terminal) to pin
65
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