ElkaTwin 61 MIDI kit retrofit Vitalka Custom Installation manual
Important:
This retrofit required to remove the ground bus or isolate her from key contacts (kapton tape for example). It is important to allow switching POLY synth keys from the MIDI interface. It probably can create more humming noise after (need to measure static noise on line out before and after midi installing)
Installation:
Select the right place to mount the LED, DIN5 MIDI connector and button on your synth (on the back panel near jacks for example).
Drill holes and try to mount it before soldering wires.
Drill dimensions:
DIN5 18mm
LED = 4.8-5mm.(better if less 5mm to strong holding in the hole)
Push button = 12.5-13mm
Board dimensions and distance between screws:
Board dimensions 105x90mm
Holes distance 94x78mm
Holes diameter 3.5mm
Do not allow the board to bend, it can break the board. Connect IDC connectors and mount the board, or hold board when inserting connectors.
All ribbon cables are 1M long, enough for placing all connections and you can cut extra length.
Panic button is not included in the kit. In case of panic - enough turn off and turn on the synth.
The next picture shows the pinout for 8 wire ribbon cable and pin number of wires:
1 - DIN5 pin 4
2 - DIN5 pin 5
3 - LEARN
4 - GROUND
5 - LED ANODE
6 - RESET
7 - V+
8 - GROUND
(7) V+ and (8) GND should be soldered on the next points:
This picture shown first (1) pin/wire on all connectors:
After soldering 8pin connector wires, time to soldering wires for key contacts.
Upper group connectors is for POLY part, downer is for BASS part of keyboard.
Board pinout and MIDI note for POLY and BASS sections: ZOOM
Some explaining to table: Bus 1 = B1, Bus 2 = B2, Bus 3 = B3, Bus 4 = B4 this busses should be connected to same busses on Elka. See schematic for details.
B1 and B2 is for BASS sections at first two octaves (counts from left to right).
B3 is for second, B4 is for third, fourth and fifth octaves on POLY section.
Solder wires to common buses and every key contact spring.
You can see that on Elka schematic notes starts reversed - from right to left. Ignore it.
So, looks like installation finished. Now time to explain how set MIDI channel. This is what you need to know for starting use this retrofit.
To teach the MIDI channel, - stop all MIDI traffic. Push the black button (LEARN) LED will blink two times and stay ON to wait for MIDI messages. When messages are received LED will blink five times and turn OFF and then will ON with every NOTE ON messages on the selected channel. Now the channel saved to memory and not changed before will be rewritten.
One small important thing - use hot glue for fix inserted connectors for protect from disconnection them during vibration when you ride on tour. Also, fix wires strong. Do not leave them holding only on soldering joints.