Sega race tv boost pin?

[Niclas]

I canot find boost pin.
I the read the wiring diagram But i dont understand where to find it on the I/O board?

 

[nem]

According to the schematic found in this manual:

http://www.progettosnaps.net/manuals/pdf/segartv.pdf

Pin 27 on the 60 pin digital input connector.