C16 & PLUS/4 Parts Location Part Number Description U11-U18 4164-2 (8) 64K x 1 dynamic RAM (PLUS/4) U5, U6 4416 (2) 16K x 4 dynamic RAM (C16) 6529B PIA U5 6529B PIA (PLUS/4) U3 6551A ACIA (PLUS/4) U1 7360/8360 TED U2 7501/8501 CPU 251641-02 7700-010/82S100 PLA 318006-01 23128 ROM Basic 3.5 8000-BFFF 318005-04 23128 ROM Basic 3.5 C000-FFFF 318005-05 23128 ROM Basic 3.5r C000-FFFF U25 317053-01 23128 ROM 3-PLUS-1 8000-BFFF (PLUS/4) U26 317054-01 23128 ROM 3-PLUS-1 C000-FFFF (PLUS/4) U26 16K ROM 3-PLUS-1r C000-FFFF (PLUS/4)