Remember for infini key to work the PCB must be able to receive said key, any failure in that and of course its not going to work.
Aka this isn't an issue with Infini Key, but and issue with your B-board.
|Darksoft: CPS3, CPS2, F3, MVS|
RGB: RECO v2, HAS v3
invzim: Jammafier v1.6b
XianXi: JNX Raiden, SC Taito Classic, SC Sega System 16/24
Frank_fjs: JAMMA Extender (Special Edition)