I wasn't able to find anything on this in Japanese or in English, so I figured I'd ask here to see if anyone knows.
Basically, I have a CDR-30A CD ROM2 and two Interface Units, one RGB modded (IFU-30) and one not (IFU-30A). I can save when I use the IFU-30A, but if I use the IFU-30, I can't. Yes, I'm using original everything, and my PC Engine is a stock CoreGrafx. The A models and the CoreGrafx all have additional metal contacts that are not there on the original PC Engine, IFU-30, and the CDR-30.
The only things that I can think of are that either the CDR-30A needs to be used with the IFU-30A or something is wrong with my RGB IFU-30, in which case I need to go buy some tools to open it and look for damage. I've already contacted the guy I bought it from, as well. Does anyone know anything about this?