THE FOLLOWING INSTRUCTIONS DETAIL THE CHANGES WHICH MUST BE IMPLEMENTED TO UPGRADE A U.S. A2000 PCB FROM REV 4.0 (or higher) TO REV 4.5 1) THE FOLLOWING COMPONENTS MUST BE REMOVED IF INSTALLED. R901, C917, C902 LOCATED LEFT OF CN601 NEAR PIN 1. C910, C911 (FIX FOR HYTEK KEYBOARDS). LOCATED OFF KEYBOARD CONNECTOR, CN300) C905, C908 C908 LOCATED ABOVE CRYSTAL X1 C905 BELOW GARY PIN 20 C230, C240 LOCATED ABOVE U204, U303 (BETWEEN PIN 34 OF THE DRIVE CONNECTOR AND U301) 2) REPLACE 1.2 KICKSTART PROM WITH 1.3 3) INSTALL RP904, RP905, RP906 ONLY IF U205 AND U206 ARE 74HC244 TYPE ICS (RESISTOR PACK IS 4.7K OHM X 5, 6 PINS). DO NOT INSTALL IF ICS ARE 74HCT244 TYPES. RP905 IS LOCATED BETWEEN U205 AND U206. RP906 IS LOCATED BETWEEN PAULA AND DENISE. RP904 IS TO THE RIGHT OF DENISE. 4) ADD .01uF CERAMIC CAP ON J300. ADD THIS CAP ON SOLDER SIDE OF PCB, FROM PIN 12 (MIDDLE PIN ON CONNECTOR) TO GROUND (USE EITHER GROUND PAD LOCATED ON SOLDER SIDE, DOWN AND TO THE RIGHT - ABOVE PAULA PINS 46 AND 48). 5) ADD 3.3 OHM 1/4 WATT RESISTOR TO PINS 11 & 20 OF U605. 6) ADD 470 OHM 1/4 WATT RESISTOR TO D800, CATHODE SIDE, TO THE SECOND PAD FROM THE LEFT, UNDER CN605. (D800 IS LOCATED TO THE LEFT OF THE RTC AT U801). NOTE: ON REV 4.3 AND ABOVE THIS RESISTOR IS ON PCB AS R1000, LOCATED TO THE LEFT OF Q302. 7) IF R5719 IS NOT PRESENT (LOCATED OFF PIN 1 OF CN400) ADD 470 OHM RESISTOR BETWEEN VCC AND CPU SIDE OF R106. 8) REPLACE GARY IC AT U102 WITH MOS TYPE (PART NUMBER 318072-01). ONLY MOS TYPE ARE IN STOCK.