We have a TFHX 1504 2C from that era, that is just now being converted from floppy to USB.
There ARE some parts that are discontinued, but most are available used, salvaged, or refurbed. We like PinPoint International for used parts 877-778-9850. Ken Bussell is our guy.
There are other companies like Sew Many Parts that have some used and salvaged parts, and if you poke around, there might be a current or even past vendor/sponsor for this board, which of course should be a top consideration. I just didn't find one during a cursory look.
Tajima's are workhorses, but I wouldn't shy away from a used Barudan.