Due to a lack of space, I have sold my Akai ME10D and ME20A. I'm leaving this page here for reference, but it is unlikely that there will be any updates.

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For those of you who are unfamiliar with the name, the ME20A is a very simple MIDI arpeggiator.  It's a very early MIDI design, so it's features are very limited.  My biggest complaint is that the arpeggios don't sync to any incoming MIDI clock signals.  I tried to add a clock input, but due to the design  I was unsuccessful.  With the help of Juergen Haible, I was able to add a gate output to the device.  This gate output can be used to drive any analog sequencer, or used to fire notes from an analog synth.  The rate of the gate outputs is then controllable via the ME20A's "Speed" control.  This schematic is Juergen's design, I just redrew it to make it a little clearer.  I also added the Akai component names to make it easier to find the places to connect the wires. The diodes can be any signal diode (1N914 or 1N4148) and you can use any general purpose transistor that you have handy.  The +5V source and ground can easily be taken from right around the 7905 voltage regulator... there are actually extra holes in the PCB for capacitors (that weren't installed in my unit) that can be used to attach to.

   I'd also like to add that this circuit could be used to give a gate signal from just about any flashing LED that you can find.  I plan to do the same mod to my Akai ME10D MIDI Delay.