==== Mod performed on MAC revH to convert to PC revH ====

  - removed U2104. (bridget bus management)
  - bypassed /BR /BG signals (removed bridget bus management) : R2122, R2124 (BG master, BG slave) connected directly to CPUs (via logic probes). R2125 (BR master) and R2123(BR slave) are bypassed with 0 ohm jumper.
  - removed 29.5 MHz oscillator on position U5403
  - populated and shorted J5401
  - added 2 bodge wires on the back PCMCIA
  - added PCMCIA to EPP bridge card.