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.  CURRENT
PRODUCTION BOARDS ARE EITHER REV 4.5 W/O NEW AGNUS, OR REV 6 W/ NEW AGNUS. ALSO
NOTE: SOME REV 6 PCBS MAY HAVE A DRAM TOWER AND STATIC COLUMN DRAMS, SOME MAY
NOT. FIELD UPGRADES ARE NOT RECOMMENDED ON REV 3.X PCBS.


26/3-2.1	A2000 FIELD UPGRADE 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.