Dont forget that, with a Japanese Saturn you have to wire the Signal wire from point A on the chip to the 8th pin of the 64IC on the cd-drive board!
I dont know why this has to be done with a Japanese saturn, but its a good thing to do it either way. The A+B solder bridge is not a 100% thing.
And dont be discouraged from the fact you have a 64pin chip. My Pal system runs just fine with the chip!

(Well, it was once a pal, Its basically fully ntsc/j now)
Here is my old thread if you are interested.
But the picture is a little outdated, I ended up getting my 5v power from the CD-Drive connector. A guide of how to do this you can find
Here
Good luck, Im sure it'll work out. If you do have issues its easy to troubleshoot. I feel like people missinterpretate the success rate.
Its more about how good the saturn is able to pick up the chip. I discovered that, when I put a original japanese disc in my saturn and start the system up with the lid closed, it would then go to the menu and pick up original or backup games at any time.
If I start the system with the lid open, It would behave very odd and read originals but no backups. So yea that being said, If it dosnt work after your first try, keep troubleshooting it!