According to the BOMARC schematic I have of the "SE" edition analog board, showing the FAN board and CRT board, there is a fan driver chip mentioned that is p/n LB1660. The datasheet for the LB1660 is here:

http://pdf1.alldatasheet.com/datasheet-pdf/view/40506/SANYO/LB1660/+30WQJUOYLXObM.ACwt+/datasheet.pdf

Says the chip can output 1.5A. But again, this schematic I have is of the SE, not the SE/30. So you'll need to verify this on your SE/30's analog board. They should be about the same though.

Also, if you want the BOMARC schematic I have, PM me with your email address and I will fire it off to you.