@tubetime Here's my video take on the build. It might all sound Greek to you, but i managed to embed English subtitles:
https://www.youtube.com/watch?v=hzqAyf1p15I

@tubetime Here's some testing

@tubetime Just finished modding the TEAC drive, all is ok!

@tubetime Almost there! I was a bit confused with the A500's floppy power connector CN12, because they use red color on the 12v cable...
Just need some cleaning and mod the drive now.

@tubetime Received the boards from PCBway. Waiting on a set of sockets and then i will update on testing.

@tubetime That's great! Just ordered a Sony to try this. Had a Power Computing external HD drive bought new decades ago, but its' GAL went kaputt. Time to get back in action..

@tubetime Thanks a whole lot! BTW, are you having the pcb for sale anywhere, or upped on, say, pcbway?