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thru -9).
All
necessary
DC
supply
voltages
for
the
rhythm
unit are supplied
by
this
chassis.
The
output
voltages are
30
V
DC,
15
V
DC, and
5.5
V
DC. The
5.5
V
output
is
not used
in
the
Model
L-
100-1
organ.
120
V AC
50/60
Hz
is
supplied
to the
power
transformer
from
an
external source.
The
secondary
AC
voltage
is
40
V
AC,
which
is
then
rectified
by
the
full
wave
bridge
of
diodes
D
1
00,
D
1
0
1
,
D
1
02 and
D103.
This
DC
voltage
is
then
filtered
by
the
combination of RlOl,
R103, ClOOA,
CI
01
and appUed
across the
30
V DC
Zener
diode
D104. The 30
V DC
is
the
supply
voltage for the amplifier
stages
Q106,
Q107
and
Ql 08 on
the
rhythm
PWB
and
the reference voltage for the
1
5
V DC
and
5.5
V DC
suppUes.
The 30
V DC
is
supplied
to the voltage
divider
of
R107
&
R108
and
fed to the voltage regulators
Ql 00
&
Ql
02,
the
output of
which
is
the
1
5
V DC
which
is
used
to
supply
all
other
circuits
on
the
rhythm
device.
The 30
V DC
is
also
supplied
to
the voltage
divider
R106
&
R105, and
fed to the
2-
emitter follower
QlOl
,
the emitter
output
of
which
is
5.5
V
DC.
QlOl
is
used
as
a
voltage regulator
and
in
conjunction with
ClOOB
provides the
filtering
for
the
5.5
VDC.
2-17.
PUSH
BUTTON
CIRCUITS
(See Figure
5-6).
One
side
of each push button
is
connected
thru
R200, 2.2K
ohm
resistor
to the 15
V
DC
supply.
The
1
5
V DC
is
available to
the
push
buttons
at
all
times,
and
if
one
is
de-
pressed
at
any
time, that particular voice
will
appear
at
the output.
When
any
of the
push
buttons
is
depressed, that
button
apphes
1
5
V DC
to
the base input
of
a
phase
shift oscillator.
As
an example,
if
the
BLOCK
push button
is
depressed,
1
5
V DC
is
apphed
to the
junction
of
RIOOB
and
capacitor
ClOOB.
This
signal
is
differentiated
by
CI
OOB
and
the
resulting
pulse
is
fed thru
DIOOB
and
Rl 05
to the base
of
Ql
OOB,
turning
it
on.
This
signal
is
fed
back
to the
base, inverted
by
the
phase
shift
network C103B, C102B,
C104B, R106B, and R107B, and
will
be
regenerative for a
period
of time determined
by RIOOB, ClOOB, and
RIO
IB.
The
decay-
time of
the
collector
output depends
upon
the values
of
ClOlB,
R105B
and R102B.
2
The
output
is
coupled through
capacitor
C105B,
resistor
R104B, and
capacitor
CI 20
to the
base
of ampUfier
stage
Ql
07,
and
after
amplification
by
Q
107 and
Q108,
it is
connected
to
R203,
the
volume
control.
TOM-TOM, BONGO,
and
CLAVES
are
similar in
operation.
The
frequencies
of
the
oscillators
are
determined
by
the values of
the
components
in
the
phase
shift
network.
When
the
BRUSH
push button
is
depressed,
+
1
5
V DC
is
suppUed
to the junction
of
Rl
16
and CI
1 1
,
and
this
supphes
bias
through
D102
to the base
of
Q
103,
tuming
"on"
the
one
shot multi-vibrator
stage,
Q103
and
Q104
for
one complete
cycle.
The
Brush Gate
transistor
Q
105
is
turned
"on"
for a
period
determined
by
CI
13
and
R120
of
the multi-vibrator
stage.
This
apphes
positive bias
through
R123, D104,
R124
to base
of
Q105,
turning
on
Q105
and
allowing white noise
to
appear
on
col-
lector
of
Ql
05,
tuned
by
CI
15
and
LI
01,
and
this signal
is
then routed through CI
1
7
and output
level
control
R126
and
R127
to
hiss
amplifier
Q106.
LOWER
MANUAL
KEYING
CIRCUITS
(See
Figure
5-6).
-
The
lower
manual
buss
line
is
connected through
CI 24 and
the base
of
Q109, which
is
a
pulse
ampUfier
stage.
Re-
sistor
R147
provides base
bias
to the
stage,
so that
with
no key
depressed,
the
collector
is
at
approximately
4.5
V
DC.
CI 24
and
R145
is
a differentiating
network which
puts
a
pulse
on
the base
of
Q109.
This
pulse
is
amphfied by Q109, and
instanta-
neously
the collector
of
Q
109
rises
from
4.5
V DC
to
approximately
1 1
V
DC
This
change
is
routed through
R
149
to the base
of
Ql
10,
which
at
an
emitter voltage of
5.5
V
and
base
bias
of
4.5
V
was
"off".
With
1
1
V
on
its
base,
QUO
turns
"on",
and
its
collector,
which was
at
1
5
V
drops
to
5.5
V. This
change
is
coupled through CI
26
and
R153
to the base
of
Qlll,aPNP
which
has
been
biased
"off"
through
R152
and R153.
The
change
in bias
turns
"on"
QUI
and
the
collector
has
an
instanta-
neous output of
+
1
5
V DC
of
about
2
milliseconds duration. This
trigger
pulse
is
defined
as
the
lower
manual
trigger pulse.
The
pulse
is
routed through whichever
LOWER
tabs are
"on"
to
trigger
the
selected voices.
Output
is
obtained
as
described
in
Paragraph
2—17.
19.
PEDAL KEYING
CIRCUIT
(See Figure
5-B).
-
A
signal
of approximately 75
mV
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