Just so happens I moved my A4000T ver 4 motherboard back into it's original case today. It has the Amiga Technologies Gmbh Label on the back.
I had moved it into a larger case shortly after getting it, to accommodate the 386 Bridgeboard. With it and Ami, all the drives, floppy, Harddrive, CDRom, etc, I need more space.
Last year I pulled all the Bridgeboard stuff out and today moved Ami back into the original case.
The "Turbo" button is a internal speak on/off button.
LeEric