First time use

  1. Turn cabinet OFF
  2. Connect JVS and both power cables to Jammafier, do not connect game PCB
  3. Turn cabinet ON, the LED on the Jammafier should immediately turn on
  4. Verify on OLED that IO board is found.
  5. Verify supply voltages on OLED.
  6. Turn cabinet OFF

Use with game

  1. Turn cabinet OFF
  2. Make sure cables from cabinet is connected to Jammafier:
    • Both JVS power cables
    • JVS ‘usb’ cable
    • Audio cables
    • VGA cable*
  3. Gently connect Jammafier to Jamma game board – the OLED display should face upwards
  4. Turn cabinet ON

Warning! Using the Jammafier in dual-power setups, i.e. game is not powered directly from the Jammafier is not supported or recommended. 

Screen Saver

The OLED display will shut down after 5 minutes of no user interaction.  It will power-up on immediately on user input, or if JVS state changes.

NeoGeo MVS UniverseBios function


If you have this bios in your NeoGeo, you can start the Jammafier with button A pressed to access the Universe Bios Menu, or button B to access test mode.

On release, the Jammafier will continue it’s startup function and initialize JVS.

Menu system

B button toggles between the different options/screens.  Button A changes/activates option.

JVS Input test

This displays active button switches on your JVS cab – useful for troubleshooting

Button 4&5 Option

Toggles between button 4&5 being active on edge connector and kick, or just kick.  This is needed for some CPS2 games.

Remap Input

You can remap the cabinets input, for normal use leave the setting at the default ‘none’. 

The available presets are:

  • None – no remapping
  • MVS 
  • MVS KOF 
  • MVS Pad
  • Tate – ‘useful’ when you have vertical games in a cab with horizontal monitor


Shows the firmware version, PCB version and serial number of the Jammafier

Save config

Saves configuration to micro-sd card.

Last Updated on 2022-08-19 by admin