Drum-machine Vermona ER9.
Repair, modernisation, MIDI.
Please read this first.



Vermona ER9


I got this device in a non-working condition.
It turned out that the power supply is the reason for the machine to be dead.
It was decided to build a new power supply and combine it on the same board with a MIDI-controller.
The Components were selected to preserve the overall design style of the device.

PSU for "Vermona ER9". Schematic

View (download)
3272x2091


The MIDI-channel number is selected by DIP-switches SA1 in binary (channel 1 code is b’0000’, channel 2 - b’0001’, channel 3 - b’0010’, etc., and channel 16 - b’1111’).
Jumper J1 determines the MIDI OUT operation as follows:

J1 MIDI OUT
Open All messages except messages for the channel selected by SA1.
Closed All messages except messages Note On/Off generated by this drum-machine.

Jumpers J2-J4 are reserved.


Vermona ER9, New PSU


In the original version the device plays continuously all the time. Turning it off is established by blocking its audio output.
To prevent the output from blocking so that one could also hear the notes coming from the MIDI IN input, I had to modify the clock-generator circuit as follows:

Clock Generator for "Vermona ER9". Schematic

View (download)
949x781


Vermona ER9, New Clock Generator


The result obtained after these and some other minor enhancements is available on the Video, web-page, or directly here.



Function Transmitted Recognized Remarks
CHANNEL Default
  Changed
X
X
10
1-16
SA1
NOTE NUMBER X 35 (Bass Drum)
38 (Snare Drum)
42 (High Hat)
47 (Tom Tom)
51 (Cymbal)
56 (CowBell)
61 (Bongo)
70 (Maracas)
75 (Claves)
Change Dump
AUX Local Control
  All Notes Off
  Active Sense
         Reset
X
X
X
X
X
X
O
O
 
"Running Status" Mode support O:  Yes
  X:   No








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