ELECTRONIC KEYBOARD
MODEL AK-900
Elenco Electronics, Inc.
Copyright © 1997 Elenco Electronics, Inc. Revised 2001 REV-A 753034
Assembly and Instruction Manual
!
WARNING: CHOKING HAZARD - Small parts,
not for children under 3 years of age.
PARTS LIST (WE SUPPLY)
Bag # Qty Description Part #
main 1 Circuit Board, fully assembled 517031
main 1 Top Case 623113
main 1 Bottom Case 623203
1 2 Button Cushions with 12 contacts 662200
1 1 Button Cushion with 2 contacts 662201
1 2 Piano Cushions with 12 contacts 662202
1 1 Piano Cushion with 13 contacts 662203
2 3 Black Piano Key Clips 626060
2 2 White Piano Key Clips with 7 keys 626061
2 1 White Piano Key Clip with 8 keys 626062
3 3 Switch Springs 680021
3 3 Switch Ball Bearings 666004
3 2 Speaker Clamps 680022
3 9 Screws 0.4” x 0.1” (10mm x 2.5mm) for Circuit Board 642103
3 15 Screws 0.3” x 0.1” or 0.2”x0.1” (7.5mm x 2.5mm or 6mm x 2.5mm) 642104
for Bottom Case, Circuit Board side, and Speaker Clamps
4 3 Switches (black plastic piece with metal contact) 549101
4 3 Switch Covers (gray plastic piece) 549102
4 4 Large Pink Buttons 626063
4 4 Large Pink Button Contacts 662204
4 2 Small Pink Buttons 626065
4 8 Small Orange Buttons 626066
4 8 Small Green Buttons 626067
4 4 Medium Blue Buttons 626064
5 1 Speaker, with plug-in connector to Circuit Board 520820
5 1 Battery Cover 626016
5 1 Battery Pad 626017
5 1 AK-900 Label 727000
5 1 Battery Wires, with plug-in connector to Circuit Board, short wire to 880012
battery contact spring, and long wire to batter y contact clip
TOOLS NEEDED
Screwdriver (Phillips type, small-medium size)
6 AA batteries (alkaline are preferred)
Tape (Scotch type will be fine)
Vaseline or grease
-1-
PARTS IDENTIFICATION
BAG 1 BAG 2 BAG 3 BAG 4 BAG 5
Piano Cushion w/
13 Contacts
Button Cushion
w/ 2 Contacts
White Piano
Key Clip
w/ 7 Keys
White Piano
Key Clip
w/ 8 Keys
Switch Spring
Switch Ball Bearing Speaker Clamp Screws
0.4” x 0.1” (10mm x 2.5mm)
for Circuit Board
0.3” x 0.1” or 0.2” x 0.1”
(10mm x 2.5mm or 6mm x 2.5mm)
for Bottom Case, Circuit Board
Side, and Speaker Clamps
Large Pink Button
Large Pink Button
Contact
Switch w/ Metal Contact
Switch Cover
Small Button
(Pink, Orange, Green)
Medium Blue Button
Battery Wires w/ Plug-in
Connector to Circuit Board
Battery
Cover
Battery Pad
Label
-2-
Piano Cushion w/
12 Contacts
Button Cushion w/
12 Contacts
Black Piano
Key Clip
Speaker
w/ Plug-in
Connector to
Circuit Board
Smaller than shown
Smaller than shown Smaller than shown
INTRODUCTION
The AK-900 Electronic Keyboard is a electronic m usic system that you put together. It has 37 keys, 8 instrument
sounds (piano, flute, violin, organ, French horn, banjo, music box, guitar), 8 tempo adjustable rhythms (pop
music, disco , march, rhumba, tango , waltz, s wing, ballad), 4 percussion eff ects (bass drum, close cymbals, open
cymbals, indian snare drum), and 1 demonstration routine along with stereo, vibrato, and tempo effects. Most
of these sounds may be combined. The user can add his/her own music to a background tune. It uses 6 “AA”
batteries (not included) or an optional AC/DC adapter. The Keyboard is mechanically assembled by the user
with no soldering required.The only tool needed is a phillips screwdriver.
Recommended for ages 10 and up. However, after the assembly and lesson are completed it will be suitable
for ages 3 and up.
WARNING:
Choking Hazard: This kit contains small parts and should be kept out of the reach of small children until
it has been fully assembled. The optional AC/DC Adapter should always be kept away from small
children.
THEORY OF OPERATION
What is Sound?
Sound
is a variation in air pressure created by a mechanical vibration. (For a demonstration of this, lay one of
your stereo speakers on the floor, place your hand on it, and turn up the volume. You should feel the speaker
vibrate. Now place a piece of paper on the speaker; if the volume is loud enough, you will see the paper vibrate).
Since the vibrations usually last for some amount of time we call the result
sound wav es
. If the vibration occurs
at a certain rate, then the sound wave will repeat itself at the same rate;we refer to this as the
frequency
of the
sound wave. Nearly all sound waves have their energy spread unevenly across a range of frequencies. You
can compare sound waves from y our voice to waves in a pond. When you speak, the movements in your mouth
create sound waves just as tossing a rock into the pond creates water waves. Sound waves travel through air
as water waves travel across the pond. If someone is nearby, then their ears will feel the pressure variations
caused by your sound waves just as a small boat at the other side of the pond will feel the water waves. When
you say a word, you create a sound wave with energy at various frequencies, just as tossing a handful of
various-sized rocks into the pond will create a complicated water wave pattern.
Just as there are sound waves caused by mechanical vibrations, there are also
electrical waves
caused by
electrical variations. Just as sound wa ves tr av el through air , electrical wa ves tra v el through wires. A
microphone
senses pressure variations from sound wav es and creates electrical wa ves at the same frequencies. A
speaker
uses the energy in electrical waves to create mechanical vibrations (sound waves) at the same frequencies. In
addition, electrical variations at high frequencies (referred to as radio frequencies) can be used to create
electromagnetic radio waves
which travel through air and are used for many forms of communication.
The subject of music is one where the worlds of art and science come together. Unfortunately, the
artistic/musician field works with qualities that depend on our feelings and so are difficult to express using
numbers while science/engineering works with the opposite - clearly defined, measurable qualities. As a result,
some of the terms used may seem confusing at first, but you will get used to them.
Let’s talk about frequency some more. Frequency is the number of repetitions per second (for sound or
electrical waves), e xpressed in units called
hertz
(Hz). The
metric
prefixes can be used, so 1000 repetitions per
second is 1
kilohertz
(kHz) and 1,000,000 repetitions per second is 1
megahertz
(MHz). The range of
frequencies that can be heard by the human ear is approximately 16 to 16,000 Hz and is ref erred to as the
audio
range. The musical world’s equivalent to frequency is
pitch
. The higher the frequency, the higher the pitch of
the sound. Frequencies above 3000 Hz can be considered to provide
treble
tone. Frequencies about 300 Hz
and below provide
bass
tone.
Loudness
(the musical term) or
amplitude
(the electronics term) is increased by
simply sending more electrical power to the speaker.
-3-
Fundamentals of Music
What is Music?
Music
is when vibrations (creating sound waves) occur in an orderly and controlled manner
forming a pattern with their energy concentrated at specific frequencies, usually pleasant to listen to.
Noise
is
when the vibrations occur in an irregular manner with their energy spread across a wide range of frequencies,
usually annoying to hear (static on a radio is a good e xample). Notice how some people refer to m usic that the y
don’t like as noise.
Another way to think of this is that the ear tries to estimate the next sounds it will hear. Music with a beat, a
rhythm, and familiar instruments can be thought of as very predictable, hence we find it pleasant to listen to.
Notice also that we always prefer familiar songs to music that we are hearing for the first time. Sudden, loud,
unpredictable sounds (such as gunfire, a glass breaking, or an alarm clock) are very unnerving and unpleasant.
Most electronic speech processing systems being developed use some form of speech prediction filters.
Take a piece of string or rope roughly 4 feet long and tie one end of it to a chair or other piece of furniture. Swing
the other end up and down so that you have a cyclic pattern, as shown:
-4-
Now swing it three times as fast (three times the frequency), to produce this pattern:
Now try to swing it five times as fast (five times the frequency), to produce this pattern:
Since the later patterns are frequency multiples of the first, we refer to them as
overtones
(the music term) or
harmonics
(the electronics term) and the original patter n is called the
fundamental
. If you could combine all
three of the above patterns onto the string then you would get a pattern which looks like this:
This combined pattern (a single fundamental with overtones) is called a
tone
(and a
pure tone
is a single
fundamental with no overtones). Notice that each pattern is more difficult to produce than the one before it, with
the combined pattern being quite complicated. And also notice that the more complicated patterns are much
more interesting and pleasing to look at than the simpler ones. Well the same thing applies to sound waves.
Complex patterns that have many overtones for each fundamental are more pleasant to listen to than simple
patterns.
All traditional music instruments use this principle, with the instrument shapes and materials perfected through
the years to produce many over tones for each fundamental chord or key that is played by the user. Grand
pianos sound better than upright pianos since their larger shape enables them to produce more overtones,
especially at lower frequencies. Concer t halls sound better than small rooms because they are designed for
best overtone performance and to take advantage of the fact that sound waves can reflect off walls to produce
different over tone relationships between both of your ears. The same thing applies to stereo sound. You may
have heard the term
acoustics
, this is the science of designing rooms for best sound effects.
The most widely used musical scale (which measures pitch) will now be introduced;for more inf ormation please
refer to the references. This scale is called the
equal temperament scale
, expressed in hertz. You might think
of this as a conversion table between the artistic and scientific worlds since it expresses pitch in terms of
frequency. Each overtone (overtone 0 being the fundamental) is divided into 12
semitones
: C, C# (“C-flat”), D,
D#, E, F, F#, G, G#, A, A#, and B. The semitones increase by the ratio 12√2, or 1.05946.
Musical notes
(tones)
are the measure of pitch and are expressed using both the semitone and the over tone, such as A3, G#4, D6,
A#1, and E2. Your AK-900 Electronic Keyboard plays notes from C3 to C6, in order across the keyboard.
(frequency in hertz and rounded off)
Up to now, the musical measures of pitch and loudness have been discussed. But many musical sounds have
the same pitch and loudness and yet sound very different. For example, the sound of a guitar compared to that
of a piano for the same musical note. The difference is a quality known as
timbre
. Timbre describes how a sound
is perceived, its roughness. Scientifically it is due to differences in the levels of the various overtones, and so
cannot be expressed using a single number.
over- C C# D D# E F F# G G# A A# B
tone
0 16.4 17.3 18.4 19.4 20.6 21.8 23.1 24.5 26.0 27.5 29.1 30.9
1 32.7 34.6 36.7 38.9 41.2 45.7 46.2 49.0 51.9 55.0 58.3 61.7
2 65.4 69.3 73.4 77.8 82.4 87.3 92.5 98.0 104 110 117 123
3 130 139 147 156 165 175 185 196 208 220 233 247
4 262 27 294 311 330 349 370 392 415 440 466 494
5 523 554 587 622 659 698 740 784 831 880 932 988
6 1047 1109 174 1245 1319 1397 1480 1568 1661 1760 1865 1976
7 2093 2217 2344 2489 2637 2794 2960 3136 3322 3520 3729 3951
8 4186 435 4698 4978 5274 5588 5920 6271 6645 7040 7459 7902
9 8372 8870 9397 9956 10548 11175 11840 12542 13290 14080 14917 15804
-5-
-6-
Now consider the following two tones, which differ slightly in frequency:
If they are played at the same time then their sound waves would be added together to produce:
Notice that the combined wave has a regular pattern of where the two tones add together and where the y cancel
each other out. This is the effect that produces the
beat
you hear in music. Two tones (that are close in
frequency and have similar amplitude for their fundamental and for each of their overtones) will beat at the rate
of their frequency difference.
Rhythm
is the pattern of regular beat that a song has.
-7-
Now observe this tone:
The frequency is slowly increasing and decreasing in a regular pattern. This is an example of
vibrato
. If the
frequency is changing slowly then it will sound like a varying pitch; a fast vibrato (several times a second)
produces an interesting sound effect.
Tempo
is a musical term which simply describes how quickly a song is played.
The Electronic Keyboard Implementation:
The AK-900 electronically creates sounds that closely resemble those from traditional musical instruments. A
quick look at the
schematic
(a graphical representation of an electronic circuit) on page 17 will show the reader
that the IC 9037 is the heart of the product. This par t is a 68-pin silicon Large-Scale Integrated Circuit made
with CMOS (Complementary Metal-Oxide-Semiconductor) technology. For more information about CMOS and
integrated circuits please refer to the references. Please refer to the schematic and the IC 9037 block diagram
and pin description on page 17 to help understand the following:
The IC 9037 is specifically designed for electronic keyboard applications. It generates a 523.252 kHz signal
which is used as a master timing reference for all operations. The 37 keyboard keys represent musical notes
C3 to C6 in the musical scale table shown earlier. These are connected directly to the IC 9037 and may be
played anytime. These tones are produced by dividing the 523.252 kHz reference down to the appropriate
frequency and then adjusting the levels of the overtones based on which instrument is being played. When you
play a note on an instrument the sound produced is initially rather loud and then decreases with time. This effect
is simulated in the envelope block in the IC 9037 and the resulting output tone also decreases with time. As
can be seen from the block diagram, there are two sets of the circuits just described to allow two notes to be
played at the same time;once additional notes are played the earlier notes will be discontinued. Since the two
most recent notes will be the loudest, this simplification from traditional instruments (such as a piano where the
strings continue to vibrate until played again) will not be easily noticed by the listener. More complex electronic
instruments will have more circuitry to simulate more notes at the same time as well as more advanced
techniques for producing over tones.
All of the button selections are handled using ten control lines in a matrix. A matrix is similar to the rows and
columns of a table. The matrix is as follows:
On power-up, the rhythm is stopped, rhythm selection is set to Pop, timbre selection is set to Piano, Tempo is
set to medium, and Vibrato is OFF.
Percussion
(drum-like) sounds are created by playing a short pattern stored in the IC 9037’s electronic memory.
All four percussion sounds may be played at the same time. If the demo or one of the rhythms is selected then
a much longer pattern is played from the part’s memory in a similar manner. This will include both the tone and
percussion circuitry just described and will be repeated until the user presses the stop button. The tempo is
adjusted by changing the rate at which this tone pattern is played from memory (by dividing the 523.252 kHz
timing reference differently). The vibrato effect is created by varying the divide ratio to the tone circuitry slightly,
which will vary the tone frequency and hence the pitch of the sound.
The outputs from the two tone circuits and the percussion circuits are combined. The two volume control
switches adjust the strength of the tone and percussion signals before combination; weaker electrical signals
will resulting in weaker sound waves from the speaker. The combined result is smoothed (to remove unwanted
higher frequency signals that were created along with the desired tone and percussion signals), increased in
strength (amplified), and applied to the speaker where it is conver ted from electr ical waves to sound waves.
If you are unfamiliar with
printed circuit boards
(PC boards) then observe the advantages that the AK-900 board
provides. Notice all of the long, thin copper traces on the board;these are equivalent to ha ving wires connecting
all of those points but is much easier to manuf acture, m uch smaller , more reliab le, easier to inspect f or mistak es,
looks nicer, and costs much less. This board has only a single layer of copper traces; circuit board technology
has progressed to where boards with 6 layers of traces are not unusual. The board also provides stable
mounting for all of the other components.
Solder
is used to connect the copper traces to the components
mounted on the board; it is metal that melts at temperatures typically between 400°F and 800°F. Electronics
manufacturers have refined their soldering processes into a fine art through the years. Observe that IC 9037 is
the only component in the AK-900 mounted directly on the printed circuit side of the board with no holes through
the board; this is called surface-mounting and today many electronics products have ALL of their components
surface-mounted due to its advantages in sa ving space (this w as not a concern on the AK-900 due to the space
required for the keys and buttons).
Column 0 Column 1 Column 2 Column 3 Column 4
pin 66 pin 67 pin 68 pin 1 pin 2
Row 0 Pop rhythm Swing rhythm Piano timbre Horn timbre Cow-Bell sound
pin 7
Row 1 Disco rhythm Tango rhythm Flute timbre Banjo timbre High-Hat sound
pin 6
Row 2 March rhythm Ballad rhythm Violin timbre Music-Box timbre Bass-Drum sound
pin 5
Row 3 Rhumba rhythm Waltz rhythm Organ timbre Guitar timbre Snare-Drum sound
pin 4
Row 4 Tempo up Tempo down Rhythm start Rhythm stop Vibrato ON/OFF
pin 3
-8-
ASSEMBLY INSTRUCTIONS
1. Take a look at each of the parts bags and compare to the Parts List. Be sure that nothing was damaged
during shipping and handling. Contact Elenco Electronics if you have any problems. DO NOT contact your
place of purchase as they will not be able to help you.
2. Lay the Circuit Board in front of you, circuit side (green side) up. Locate the Button Cushions and Piano
Cushions from Bag #1. Place them onto the Circuit Board one at a time in the arrangement shown in Figure
A. The pegs on the Cushions fit into the holes in the Circuit Board but will be loose;flip the Board over to the
components side and pull on each of the pegs (be careful not to bend the red LEDs on the circuit side while
doing so), see Figure B. The Cushions should now be flush on the Circuit Board.
-9-
Figure C Figure D
Figure A
Figure B
Button Cushion
w/ 12 Contacts
Button Cushion
w/ 2 Contacts
Piano Cushion
w/ 12 Contacts
Piano Cushion
w/ 12 Contacts
Piano Cushion
w/ 13 Contacts
Green Side of
the PC Board
Component Side
of the PC Board
LEDs
Pegs
3.
Lay the Top Case upside-down in front of you. Locate the Switches (Bag #4), Switch Covers (Bag #4), Switch
Springs (Bag #3), and Switch Ball Bearings (Bag #3). Make sure the metal contacts are bent up 45
O
(otherwise they may not contact the circuit board), and that they are not damaged. Place a Spring into the
hole in the side of one of the Switches (as shown in Figure C). Place some Vaseline or grease into the ball
grooves in the switch slots on the inside of the Top Case (to ensure the Switch will switch smoothly) and a
drop on the Switch Spring. Place a Ball Bearing onto the Spring (the Vaseline helps hold the Bearing in place)
and carefully place the Switch into one of the switch slots, being sure not to drop the Bearing while doing so.
Next, press a Switch Cover into the Switch from the outside of the Top Case while holding the Switch in place
on the inside of the Case (as shown in Figure D). Be sure the Switch moves properly between each of the
switch settings and then install the other two Switches in the same manner.
Ball Bearing
Spring
Switch
Switch Covers
Switches
4.
Locate the Black and White Piano Key Clips (Bag #2). Place the White Clips into the inside of the Top Case
(as shown in Figure Ea). There are 3 small pegs (one for each clip) on the inside for alignment. The tab at
the end of each key must slide into its slot on the front of the Case (the “bottom of the keyboard”) so that it will
not be visible (as shown in Figure Ea). The White Clip with 8 keys (the others have 7) will have to be placed
so that its “extra” key is the most distant key from the speaker slot. Next, lay the Black Clips onto the White
Clips from the inside, using the alignment pegs again (as shown in Figure Eb).
-10-
White Piano Key
Clip w/ 7 Keys
White Piano Key
Clip w/ 8 Keys
Top Case
Figure Ea
Alignment Pegs
White Piano Key
Clip in Case Slots
Figure Eb
Alignment Peg
Black Piano Key Clips
-11-
5.
Locate the buttons (Bag #4). Attach the 4 Large Pink Button Contacts to the Large Pink Buttons as shown in
Figure F. Now place the 4 Large Pink Buttons, the 8 Small Green Buttons, the 8 Small Orange Buttons, the
4 Medium Blue Buttons, and the 2 Small Pink Buttons into the inside of the Top Case as shown in Figure F.
Carefully lift up the Top Case without tipping it (so that the buttons don’t fall out) and compare it to the picture
on the box for your Electronic Keyboard. It should match, except for 2 small holes for the red LEDs which will
be added with the Circuit Board. Correct your buttons arrangement now if necessary.
Green Green Green Green
Green Green Green Green
Blue
Blue
Orange Orange Orange Orange
Orange Orange Orange Orange
Blue
Blue
Pink
Pink
Large Pink Button
Small Green Button
Medium Blue Button
Small Orange Buttons
Small Pink Buttons
Large Pink Button Contact
Figure F
-12-
6. Straighten the red LEDs (Light-Emitting-Diodes) on the Circuit Board so that they are standing straight up
(they may have been bent to protect them during shipping). Place the Circuit Board into the Top Case,
components side facing you, as shown (it is aligned using 8 tabs on one side and 2 tall screw holes on the
other side). Make sure the red LEDs are still straight and will be visible from the outside and that you don’t
knock any of the buttons out of position. It is a good idea to elevate the unit enough so that it isn’t resting on
any of the buttons (otherwise, some buttons might be knocked out of position and won’t work properly).
Secure with 3 small side Screws (0.2”x 0.1” or 0.3” x 0.1”, from Bag #3) and then 9 large Screws (0.4”x 0.1”,
also Bag #3) as shown. Note that not all of the screw holes are used. Now flip the Top Case over and again
compare it to the picture of it on the box. It should look the same. Press each of the buttons to be sure they
depress properly. If not, unscrew the Circuit Board and check the arrangement of your buttons.
Figure G
Small Side Screws
Large Screw
Component
Side of the
PC board
CAUTION: IMPORTANT
Make sure that the PC board
goes under the tabs on the case
as shown.
Component
Side of the
PC board
Tab
Green Side
of the PC
board
LED
7. Place the Speaker (Bag #5) in its slot next to the Circuit Board and plug its connector into the Circuit Board.
The tab on the speaker connector should be facing the Speaker so that the connectors “lock” together. If the
tab is on the wrong side then the Speaker will be wired incorrectly and will not work.
8. Place the Speaker Clamps (Bag #3) as shown in Figure I to hold the Speaker in place and secure with two
Screws (0.2” x 0.1” or 0.3” x 0.1”, also Bag #3).
-13-
Figure H
Speaker
Connector
Connector
Figure I
Speaker Clamps
Small Screws
9.
Connect the Battery Wires (Bag #5) to the Circuit Board by plugging in the connector (as shown in Figure J). The
tabs on the connector should be facing the Speaker so that the connectors “lock” together. If the tabs are on the
wrong side then the product will be wired incorrectly and will not work. Now place the Bottom Case alongside the
Top Case. Spread the Battery Wires into the Bottom Case (using the small pegs as a guide for the long wire) and
press the battery contact spring and batter y contact clip into position without breaking the wires, as shown. The
clip will be a snug fit and you may need to tap it with a screwdriver to get it in all the way. Hold the long wire into
position using several pieces of tape.
-14-
10. Place Bottom Case onto Top Case (upside down) and secure with ten Screws (0.3” x 0.1” or 0.2” x 0.1”,
Bag #3), as shown in Figure K.
Figure K
Small Screw
Figure J
Battery Contact Clip
Battery Contact Spring
Scotch Tape
Bottom Case
Connector
OPERATING INSTRUCTIONS
Turn the unit on and adjust the speaker volume as needed (you may adjust the rhythm and master volumes
separately). You may use the ke yboard and custom drummer (the big pink buttons) by themselves or combined
with background music. The orange buttons provide background dance music; press one of them and then the
start button. The blue DEMO button plays the demonstration tune “Greensleeves”;to stop the demo, press the
DEMO button again. The green buttons select which instrument the keyboard is simulating (piano, flute, violin,
organ, french horn, banjo, music box, guitar). Use the small pink buttons to change the tempo of the demo or
the dance music. The Vibrato button turns the vibrato effect ON/OFF.
This product operates with six AA batteries. The unit will not sound as usual if the batteries are weak, in this
case try changing the batteries. For longer battery life take out the batteries if the unit will not be used f or a long
time and use alkaline batteries.
You may also operate this product with an AC/DC Adapter that has a 9V output voltage and 400mA current
rating. This may be purchased through Elenco Electronics or at your local electronics store.
WARNING FOR USE OF AC/DC ADAPTER:
The Adapter should be regularly examined for potential hazards of damaged cable, plug, and enclosure. In the
event of such damage the adapter must not be used until such damage has been properly removed.
The Adapter must comply with CEE publication -15.
11. Make sure the Power switch is OFF. Insert 6 AA batteries into the back of the unit being sure to orient their
positive and negative terminals properly, as shown in Figure L (if you intend to use the optional AC/DC
Adapter then you don’t need batteries). Remove the backing from the Battery P ad and stick it on the Battery
Cover, then place the Cover in its slot on the Bottom Case to secure the batteries. Place the AK-900 Label
in the center of the Bottom Case.
-15-
Figure L
Label
AA Battery
-16-
QUIZ
1. Sound waves travel through air just as electrical waves travel through __________.
2. A microphone converts sound waves into __________ __________.
3. Pitch is the musician’s term for __________.
4. Mechanical variations in a loud and unpredictable manner will seem more like noise than __________ to a
listener.
5. Traditional music instruments produce many __________ for each fundamental.
6. Musical note G5 has a frequency of __________ Hz (refer to the musical scale).
7. The main proper ties of a musical sound are loudness, pitch, and __________.
8. Two tones, with frequencies of 250 Hz and 255 Hz and similar loudness, will produce a __________ when
played together.
9. ________ is adjusted in the AK-900 by changing the rate at which a tone pattern is played from memory.
10. Long, thin copper traces connect electronic components on __________ __________ __________.
Answers: 1. wires; 2. electrical waves;3.frequency;4.music; 5. overtones; 6. 784; 7. timbre; 8. beat;
9. tempo; 10. printed circuit boards.
TROUBLESHOOTING GUIDE
Symptom: Keyboard doesn’t work at all.
• Make sure that the batteries are new and that they are installed with the correct polarity.If using the optional
AC/DC Adapter then make sure it is undamaged and plugged in.
• Make sure the ON/OFF switch is ON.Make sure the volume controls are not at the lowest setting.
• If the red LED next to the ON/OFF switch is off then flip the ON/OFF switch several times, pressing it hard.
• Be sure that none of the wiring connections were broken, are contacting any other metal (creating a “shor t
circuit”), or are wired wrong.
• Be sure that there is no physical damage to the Main PCB.
Symptom: Sounds don’t sound normal, as if out-of-tune.
• Make sure that the batteries are new and that they are all installed with the correct polarity.Alkaline or carbon
zinc batteries are preferred.
Symptom: Some of the keys, buttons, or switches do not work.
• Be sure all the keys, buttons, and switches are properly situated as in assembly steps 2-5.
• Examine the Cushions on the Circuit Board, make sure they are laying flat on the Board and that they are not
damaged.
• Be sure there is no physical damage to the components or copper traces on the Circuit Board.
Note: Contact Elenco Electronics, Inc. at (847) 541-3800 or e-mail us at elenco@elenco.com if you need
further assistance. DO NOT contact your place of purchase as they will not be able to help you.
-17-
SCHEMATIC DIAGRAM
Oscillator
OSC1
OSC2
KEY1
KEY2
KEY36
KEY37
R0
R1
R2
R3
R4
Direct
Keyboard
Logic
Matrix
Control Key
Logic
Timing Divider
Tone1
Generator
Tone2
Generator
Rhythm
Generator
Percussion
Generator
Tempo
Circuit
Melody Control
& PLA
D/A Output
Driver
Envelope Circuit
Envelope Circuit
Driver
OUT1
ENV1
ENV2
OUT2
BD
SD
HH
CB
VIBRATO VDD
DEMOVSSTEMLEDCO C2 C4
C1 C3
IC 9037 BLOCK DIAGRAM
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IC 9037 Pin Description
Internal
Pin No. Pin Name I/O
Connection
Description
1, 2 C3, C4 0 NMOS Matrix control key scanning outputs
3 - 7 R4 - R0 I CMOS Pull-High Matrix control key scanning inputs
Direct key inputs
8 - 44 KEY1 - KEY37 I CMOS Pull-High There are 22 full-scale and chromatic-key inputs for playing.
The scale is from C3 to C6.
45 VSS I - Power supply (ground)
46 DEMO I CMOS Pull-High
ON/OFF demo song control input
The title of the demo song is “Green Sleeve”.
47 OUT1 O Transmission Gate Channel 1 tone output
48 ENV1 O CMOS Channel 1 envelope effect pin
49 OUT2 O Transmission Gate Channel 2 tone output
50 ENV2 O CMOS Channel 2 envelope effect pin
51, 52 TEST1, TEST2 I/O CMOS For IC test only
53 TEMLED O NMOS Open Drain Tempo indication output
54 VDD I - Power supply (positive)
55 VIBRATO O CMOS Vibrato signal output
56 RESET I CMOS Pull-High Power-on reset pin
57 TEST3 I/O CMOS For IC test only
58 OSC1 I - Oscillator input
59 OSC2 O - Oscillator output
60, 61 TEST4, TEST5 I CMOS For IC test only
62 CB O - Cow-Bell pulsatile signal output
63 BD O - Bass-Drum pulsatile signal output
64 SD O - Snare-Drum pulsatile signal output
65 HH O - High-Hat pulsatile signal output
66 - 68 C0 - C2 O NMOS Matrix control key scanning outputs
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GLOSSARY OF TERMS
Acoustics The science of designing rooms for best sound effects.
Amplitude A measure of the strength of an electronic signal.
Audio The range of sounds that can be heard by the ear.
Bass T ones Low frequency sound, usually below 300 Hz.
Beat A pattern in musical rhythm caused by 2 tones at different frequencies
(usually close), so that they regularly form highs and lows in loudness.
Equal Temperament Scale A musical scale for measuring pitch.
Electrical Waves Electrical energy similar to sound waves but caused by electrical
vibrations and traveling through wires.
Electromagnetic Radio Waves Electromagnetic energy similar to electrical wa v es b ut caused b y electrical
vibrations at higher frequencies and traveling through air ; used for many
forms of communications.
Frequency The rate at which a pattern or wave repeats itself.
Fundamental The lowest (and usually the loudest) frequency in a tone.
Harmonics The electronics term for frequencies that are exact multiples of a lower
frequency (the fundamental) produced by the same source.
Hertz (Hz) The number of repetitions per second.
Integrated Circuit An electronic circuit that has been made very, very small.
Kilohertz (kHz) The number of repetitions per second, expressed in thousands.
Light-Emitting-Diodes (LEDs) A device which conver ts electrical energy into light.
Loudness A measure of the strength of sound waves, also called volume.
Megahertz (MHz) The number of repetitions per second, expressed in millions.
Metric System An international system of measurement.
Microphone A device which conver ts sound waves into electrical waves.
Musical Note A measure of the pitch of a sound, expressed using semitones and
overtones in a musical scale.
Noise Mechanical vibrations (sound wav es) occurring in an irregular manner with
their energy spread across a wide range of frequencies, usually annoying
to hear.
Overtones The musical term for frequencies that are exact multiples of a lower
frequency (the fundamental) produced by the same source.
Percussion Sounds Drum-like, hitting one thing against another.
Pitch The musical world’s term for frequency, expressed using a musical scale;
may be perceived differently between people.
Printed Circuit Board A board for mounting electronics components that has copper traces
“printed” on the surface for connecting the components instead of using
wires.
Pure T one A fundamental frequency with no overtones.
Rhythm The pattern of regular beat that a song has.
Schematic A graphical representation of an electronic circuit.
Semitones The division of notes within each overtone on the musical scale.
Solder A metal that melts at temperatures between 400°F and 800°F;it is used to
connect electronic components to each other or to copper traces on
printed circuit boards.
Sound A variation in air pressure caused by a mechanical vibration;our ears can
usually feel this.
Sound Waves Air pressure waves caused by mechanical vibrations.
Speaker A device which conver ts electrical waves into sound waves.
Tempo A musical term which describes how quickly a song is played.
Timbre The quality of sound that separates tones equal in pitch and loudness but
perceived differently, it is due to differences in the levels of the various
overtones.
Tone A sound with a fundamental and overtones.
T reble T ones High frequency sound, usually above 3000 Hz.
Vibrato When the frequency of a tone is slowing increasing and decreasing at a
regular rate.
FOR FURTHER READING
(These are available through Elenco Electronics Inc., unless stated otherwise).
Evans A. (1992).
Making Sense of Sound
. Sams (61026)
Sundberg J. (1991).
The Science of Musical Sounds
. Academic Press. Not available through Elenco
Electronics, try your local bookstore or library.
Pierce J. R. (1983).
The Science of Musical Sound.
Scientific American Books. Not available through Elenco
Electronics, try your local bookstore or library.
Douglas A.(1976).
The Electronic Musical Instrument Manual
.Tab Books (#832). Not available through Elenco
Electronics, try your local bookstore or library.
Penfold R. A. (1995).
Music Projects
. Sams (67052)
Rezurch I. (1996).
Electronics Terminology
. Sams (67013)
Mileaf H. (1978).
Electricity 1-7
. Sams (159523)
Johnson J. R. (1994).
Schematic Diagrams
. Sams (61059)
Kamichik S. (1996).
Digital Electronics
. Sams (61075)
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Here are some other exciting projects from Elenco you can build.
SOLDERLESS KITS
35mm Camera Kit with training course
Model AK-540
Now you can learn all about photography with our new
Camera Kit. Our training manual will teach you everything
you need to know about light, film, speed, exposure,
development, and much more. And best of all, you’ll have a
working camera “you built” when you’re finished.
Talking Clock Kit with training course
Model AK-220
This easy-to-build kit will teach you how electronic voices
are made. Model AK-220 uses analog hands to display time
and has hourly reports. Wake up to a rooster crowing in the
morning.
RADIO CONTROLLED CAR KIT
The Turbo King is our newest solderless kit. R/C cars are the hottest
thing going, and you can build your own from the ground up.
You’ll learn all about gears, motors, RF frequency and more
from our detailed assembly and training manual. Before
you know it, you’ll be ready to race!
7 Radio Functions.
Flashing T op Light.
Single Channel.
Model AK-870
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DELUXE KITS
Stereo Cassette Kit with training course
Model AK-200
Easy-to-build kit teaches you basic mechanical and
electronic circuits. You will have fun building this kit and
learning how a tape player works. Lesson manual teaches
magnetic recording, audio amplifier theory, speed control,
mechanical switching, and much more. Clear plastic case
allows you to show your friends your accomplishments.
Headphones included. Requires two (2) “AA” batteries.
Digital Roulette Kit with training course
Model AK-300
This Digital Roulette Kit is just like the real thing. With a
push of a button, the LEDs spin round and round. Where
they stop is anybody’s guess. Its unique design includes
“pop out” chips of different values. Enjoy hours of fun with
this game of chance. Requires one (1) 9V battery.
Clear T elephone Kit
with training course
Model AK-700
This is our most popular kit. Our Telephone Kit will teach you
all about communications. You will actually build your own
phone and be able to make and receive calls . The clear plastic
case lets you see all of the working components. It even has
flashing neon lamps when the phone rings.
FM Wireless Microphone Kit
Model AK-710
Now you can hear your voice on the radio! This kit will have
you singing in no time at all. After following our easy
assembly manual, you’ll be ready to transmit your voice on
an actual FM radio. Range up to 100 feet. Requires two (2)
“AA” batteries.
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All kits on this page require soldering.
Elenco Electronics, Inc.
150 W. Carpenter Avenue
Wheeling, IL 60090
(847) 541-3800
http://www.elenco.com
e-mail: elenco@elenco.com
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