ocr: ATARI 520ST IMEG UPGRADE MODS REAR VIEW OF U15 CHIP PIN LAYOUT/WIRE HOOKUP In this diagram the Pin layout numbers of the 015 memory controller chip and the (3) lines which will supPly the 3 new buss lines on the new chips are shown. The wire which connects to pin #22 or (A). in the diagram be ru to the other side of the board and supply the CAS High buss of the #15 Pins of the new high order byte eroup of memory chips. The wire from Pin #21 or (B) will go to the #15 pin buss line of the new CAS Low set of chips (U16 to U301:. line Lastly tormed the on wire from Pin #18. or (C) will be used to ...