Oberheim 4 / 8-Voice FVS-1 MIDI retrofit Vitalka Custom (one common key bus) Installation manual
This MIDI board will work only with early type of keyboard. Before 1977. With one common bus.
Installation:
To your good usability select the friendly place to mount the LED, DIN5 MIDI connector, button and PCB. Mount connector, LED and button before soldering wires.
Drill dimensions:
DIN5 = 18mm.
LED indicator = 6mm.
Push button = 12.5-13mm.
Be careful with drilling hole for button, it have small range to get hole too big.
Board dimensions and distance between screws:
Board dimensions 102x50mm.
Holes distance 94x40mm. - Use it for drill holes for board mounting.
Holes diameter 3.5mm.
All ribbon cables are 90cm. long, enough for placing all connections and you can cut extra length. Reset "Panic" button is not included in the kit. If you prefer to install it part number is E-Switch RP3502MABLK
Do not allow the board to bend, it can break the board. Even inserting connectors
All ribbon cables are 90cm. 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.
This picture shown first (1) pin/wire on all connectors:
All next wire should be connected to each key contact or to the main board:
The next picture shows the pinout for 8 wire ribbon cable and pin number of wires:
Same you can see on bottom side of PCB for more convenience.
You will need to connect wire 4 (GND) with LED and button. All other wires in this kit required only one point of soldering.
Ribbon cables pinout for better visual understanding. Even if wires go out on opposite side of connector, it still on same sequence - wire 1 at down or right on face to you. DIN5 shoved from legs side.
(7) V+ and (8) GND should be soldered on the next points:
This points located on keyboard PCB. You can solder wires near tantalum capacitor which located near connectors.
Board pinout and MIDI note:
Solder wires to key contacts and common bus. Find key contacts for note C (Do) on the first octave and solder wires from the X2 (Blue) connector. Starting from wire 1. When you finish it, your last wire will be 12 and note B (Si) on this octave. Repeat all this on every octave.
On X5 (Red), also start from wire 1 - C (Do). Skip others that marked "skip" on table. Wire 13 from X5 connector should be soldered to common key contact bus.
Process for set MIDI channel: User operations
1. Stop all MIDI traffic.
2. To teach with which MIDI channel synth will work - push the black button (LEARN) LED will blink two times and stay ON to wait for MIDI messages at one of 16 channels. He will in OMNY mode.
3. Send any note on the MIDI channel which you want for this synth.
4. When the synth receives MIDI messages, LED will blink five times and turn OFF. It indicates that channel was received and saved. Then will ON with every NOTE ON messages on the selected channel.
5. Now the channel saved to memory and will never change before you push LEARN button again and starts settings process again.
In case of panic: Stop MIDI traffic on working channel. Push reset button (if installed) or turn ON/OFF the synth.
At moment when synth power on, all keys will be sound less a half second. If on this moment MIDI commands will received on saved channel it can be cause of panic.
One small important thing - use hot glue to fix inserted connectors to protect from disconnecting them during vibration when you ride on tour. Also fix wires strong. Do not leave them holding only on soldering joints.
Last update: 11 March 2026.
