Elta KE-3 analogue squarewave keyboard with accompaniment but no rhythm
Angeltone DM-200

Elta KE-3

Elta, Germany

This small beginners/ toy keyboard is something really bizarre, because it has 8 nice accompaniments with even arpeggio, but no rhythm(!). Its warm squarewave sound and technology resemble very much the Angeltone DM-380/ Fujitone 3-A. (see there) although it has less features. It has also 8 nice demo melodies. Unfortunately at least in unmodified state a keyboard matrix flaw prevents to play certain notes simultaneously despite it is 2 note polyphonic, and volume is too loud and can not be set reasonable low.

On the box is still a tag showing that the German initial retail price was 89DM (about 40€), and the keyboard picture on the box has a crossed out brand label "ANGELTONE", which apparently was the genuine manufacturer of this small tablehooter. It was also released as Fujiyama 230 (by "Japan Design"?, seen on eBay).

crossed-out Angeltone logo on the box photo

main features:

Elta Art.-Nr. KE-3

eastereggs:

modifications:

  • missing keyboard matrix diodes added.

    • notes:

    This strange instrument seems to be a simplified variant of the Angeltone DM-380 hardware and has no analogue percussion section anymore to reduce cost. Like the similar HBATEC it has a Zilog brand CPU, but this CPU resembles more the Angeltone one since it has 40 pins (HBATEC has 28), no organ chord mode and supports a 2nd arpeggio button. But unlike both, it does not support 16 rhythms nor a fingered chord mode in the keyboard matrix (although in supports 49 keys). Unlike the Angeltone DM-380 and HBATEC, when "rhythm" is started, the accompaniment does not stay silent when the "fingered" button of the "auto bass chord" panel section is not pressed (by the lack of rhythm otherwise it wouldn't play anything); instead it always plays a fixed key accompaniment while all keys play the main voice, which also hints that this CPU was likely never intended to have real rhythm. When "fingered" is enabled, the left keyboard section is in single finger chord mode (only accompaniment, no organ chords); after selecting a chord, you can switch it "off" again to use the full keyboard for melody play together with that chord, but the arpeggio still works only while "fingered" is enabled, which looks like a design flaw. Another bug is that with "rhythm" off and "fingered" enabled, the main voice stays monophonic despite there is no organ chord mode and thus all keys play only the melody voice. The accompaniment button shape was obviously inspited by the rubber effect pad buttons of Casio MT-540.

    Generally the Elta KE-3 sounds much like the Angeltone DM-380/ Fujitone 3-A; the only main differences are the digital volume and power buttons (with auto power- off), the 64 step resolution tempo control (most steps are in the slow range) and the simple sequencer (monophonic record/ playback with fixed key accompaniment, no edit). It also features many nice sounding squarewave demo melodies, those play in an endless sequence but the start melody can be selected by pressing its corresponding piano key together with the "demo" button.
     

    circuit bending details

    The hardware of the Elta KE-3 is based on the "Zilog KZ282" CPU (40 pin DIL). It is basically a very simplified successor of the HBATEC keyboard. To reduce part count, the analogue percussion was completely omitted, so it only plays squarewave accompaniment. Despite this, the small PCB still contains a lot of discrete components (analogue envelope controls, auto power- off etc.). Extremely bizarre is that this PCB (labelled "S2312, 9012  2002" and "TC370   91 2 5") has white component placement marks printed on its top, but a lot of components are soldered in totally different places those contradict the marks (e.g. a transistor is where a capacitor should go and vice versa etc.). I never saw such a messed up PCB elsewhere in a consumer product; I can only imagine that this thing was either a prototype or a new CPU was released that had a changed pinout and thus the poor factory pieceworkers were urged to solder the discrete components differently to adapt the given PCB to it (it must be badly confusing to assemble such PCBs). E.g. there was a shorted solder joint that looked like a fault, but when cut open, the envelope of the 2nd main voice (or the arpeggio) plays too short, thus it was likely intended to be shorted and I had to solder it back.

    keyboard matrix

    5
    6
    7
    10
    3
    4
    25
    16
    17
    18
    22
     
    CPU pin
    in 1
    in 2
    in 3
    in 4
    in 5
    in 6
    in 7
    in 8
    in 9
    in 10
    out P
    in / out
     
    o
    o
    o
    o
    o
    o
    o
    o
    o
    o
     L.
    /rec
    out 1
    30
    o
    o
    o
    o
    o
    o
    o
    o
    o
    o
     L.
    /tempo
    out 2
    34
    o
    o
    o
    o
    o
    o
    o
    o
    o
    o
     L.
    /tempo
    out 3
    19
    o
    o
    o
    o
    o
    o
    o
    o
    o
    o
     L.
    /fingered
    out 4
    35
    o
    o
    o
    o
    o
    o
    o
    o
    o
     C.
    Y/C
     
    out 5
    36
    volume
    +
    volume
    -
    C.
    arpeggio1
    C.
    arpeggio2
     C.
    fingered
    C.
    off
    tempo
    -
    tempo
    +
    R.
    start/stop 
    R.
    rhumba
     T.
    base
    out 6
    37
    R.
    march
     R.
    pops
    R.
    bossanova
    R.
    tango
    R.
    disco
    R.
    16 beat
    R.
    waltz
    R.
    synchro
    R.
    start
    R.
    stop
     T.
    hihat
    out 7
    38
    R.
    start/stop
    O.
    piano
    O.
    oboe
    O.
    harpsichord
     O.
    xylophone
    O.
    piccolo
    O.
    mandolin
    O.
    organ
    O.
    guitar
    record 
     T.
    tom
    out 8
    39
    playback
    demo
    1
    demo
    2
    demo
    3
     
     
     
     
     
     power
    off
     
    out 9
    2

    The input lines are active-low, i.e. react on GND. Any functions can be triggered by a non- locking switch in series to a diode from an "in" to an "out" pin. The matrix was sorted by ascending key notes ( = ribbon cables in Angeltone DM-200).
     

    legend:
    "o"
    		 = keyboard key
    underlined
    		 = function needs locking switch (i.e. stays active only so long the switch is closed)
    R.
    		 = preset rhythm
    O.
    		 = preset sound ('orchestra')
    C.
    		 = chord
    L.
    		 = led out
    T.
    		 = percussion trigger out
    orange
    background     		 = easteregg (unconnected feature)

    eastereggs:

    • 5 lower and 7 higher note keys addable
    • 2 different arpeggios
    • separate rhythm start & rhythm stop button
    • 3 OBS demo buttons
      not needed - you can select demos anyway with normal "demo" button + leftmost keys.
       
    • Y-C switch
      a locking switch here changes the single finger chord playing method from Yamaha to Casio (see here).
    • percussion trigger outs
      Like with the HBATEC, there are LEDs and percussion trigger outs hidden in the matrix. But by the lack of its discrete analogue percussion circuits it would be very difficult to add them.
    fix key matrix flaw

    A design flaw in the Elta KE-3 keyboard matrix prevents to play any 2 note combinations those share the same key matrix row. To fix this, solder a diode into each matrix input line of the keyboard PCB (ribbon cable).

    reduce volume

    The instrument plays always quite loud and even at the lowest setting it is still loud enough to annoy neighbours tonight (although at least the speakers sound nicely warm and don't distort). To reduce the volume, solder a 10 Ohm resistor into the loudspeaker line.
     

    pinout KZ282

    The "Zilog KZ282, R417, LIL8911ASIC" (40 pin DIL) is a squarewave home keyboard CPU with 2 note polyphonic main voice and accompaniment. It strongly resembles the KZ283 of the HBATEC keyboard, but has 40 pins to support a conventional keyboard matrix. The 2 main voice channels have analogue capacitor envelopes controlled through each a short envelope trigger pulse /ME and a duration signal /MH that indicates how long the key is held. The 4 step digital volume control uses a 2 bit output. Pin 20 outputs something that looks like the clock divided by 2. Pin 22 combined with the keyboard matrix outs can control LEDs and 3 (unused) percussion triggers.

    Pinout comparison with the Zilog Z86C30 datasheet strongly hint that this is a Zilog Z86C40 MCU (236 bytes RAM, 4KB ROM, 16MHz). Even the in-only and out-only port pins match. The port pin order is a mess, don't ask me why. This pinout is based on my own hardware observation combined with above MCU. Line names were chosen by me to describe their functions (partly inspired by Casio naming conventions).
     
    pin name line purpose
    1 R//W   read/write out (not used)
    2 P25 /KO9 key matrix out
    3 P26 /KI5 key matrix in
    4 P27 /KI6 key matrix in
    5 P04 /KI1 key matrix in
    6 P05 /KI2 key matrix in
    7 P06 /KI3 key matrix in
    8 P14 C1 chord tone 1 out
    9 P15 C2 chord tone 2 out
    10 P07 /KI4 key matrix in
    11 VCC   supply voltage +5V
    12 P16 B bass tone out
    13 P17 /APO standby out
    14 XTAL2   crystal out
    15 XTAL1   crystal in / clock in (LC oscillator, about 7MHz)
    16 P31 /KI8 key matrix in
    17 P32 /KI9 key matrix in
    18 P33 /KI10 key matrix in
    19 P34 /KO3 key matrix out
    20 /AS   address strobe out (NC, about 3.3MHz = half clock frequency?)
    21 /RESET   reset
    22 P35 /KP matrix percussion & led out
    23 P37 /MH1 melody channel 1 held
    24 P36 M1 melody channel 1 tone out
    25 P30 /KI7 key matrix in
    26 P00 /VOL0 volume bit 0 out
    27 P01 /VOL1 volume bit 1 out
    28 P10 /ME2 melody channel 2 & arpeggio envelope pulse out
    29 P11 M2 melody channel 2 & arpeggio tone out
    30 P02 /KO1 key matrix out
    31 GND   ground 0V
    32 P12 /ME1 melody channel 1 envelope pulse out
    33 P13 /MH2 melody chanel 1 held
    34 P03 /KO2 key matrix out
    35 P20 /KO4 key matrix out
    36 P21 /KO5 key matrix out
    37 P22 /KO6 key matrix out
    38 P23 /KO7 key matrix out
    39 P24 /KO8 key matrix out
    40 /DS   data strobe out (not used)

    All demos use a monophonic main voice with only the standard accompaniment and arpeggio, but they switch them in nice ways. Names were partly identified by the Angeltone DM-200 manual, which however lists them in different order and also some names seem to be different (possibly Chinese names of well known melodies).

    The demo melodies are:

    1. Oh La Paloma Blanca
    2. Night in Moscow Suburb
    3. Music Box Dancer  (here called "The Concert"?)
    4. Tea- Picking Melody (a Chinese tune)
    5. Edelweis (slow waltz)
    6. Wa Haha (a Russian tune?)
    7. For Elise (here called "The Youngman"?)

    Angeltone DM-200

    Angeltone DM-200 - electronic keyboard

    This is another keyboard based on the same hardware class like Elta KE-3. Unlike the latter, it has matrix diodes and thus no polyphony flaw. But it lacks the power-off button (only auto power- off) and plays a different arpeggio.

    different main features:

    panel PCB has empty solder holes Angeltone, model: DM-200, made in China

    eastereggs:

    ANGELTONEThe golden "ANGELTONE" logo sticker on the case is made of hologram foil. The main PCB (labelled "S2011") is less messed up and not hacked together; there are only a few omitted discrete components printed on it. The manual is a mess of Engrish misspellings, and its German translation is even worse. The speaker of my (used) specimen was bent and distorted horribly; after manually aligning the diaphragm it now sounds fairly ok. This instrument was also released as ESD TK-25 (told by eBay vendor).
     

    Likely a fullsize variant with Fujitone 3-A case without drumpads and 'rec' & 'play' instead of custom drummer 'play/space' & 'program'  buttons was released by Hua Li (only 2 Chinese characters) as DM-250. (Box shows brand "discover MTC" and "MusiTech Collection" with an MC-3 case (dummy?) MusiTech MT-4000, seen on internet.) I expect this to have a KZ282 CPU due to the sequencer buttons. Due to omitted drumpads likely also this one lacks percussion hardware.
     

     removal of these screws voids warranty...    
    WarrantyVoid
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