Each 303 power converter board has two AT&T FW300 DC-DC 3V converters on board.

60 A per DC brick, 120 amps per board. This is screwdriver-melting stuff!

The 512T power board provides 5V and 12V DC to the VME bus and IO4 board.

The system controller has it's own power converter as well as:

Dallas RTC and NVRAM

system controller EPROM

Motorola 68hc11 MCU