Fix a 800XE / 65XE / 130XE with bad GTIA Chip

{Recovered Atari Sector}
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ndary

Post by ndary on Jul 9, 2017 at 12:36pm
Hi All,

you probably know that there is a batch of ATARI XE computer out there with Bad GTIA chip, these computers where sold in the early 90ies in east Europe.


here is a image of an ATARI 130XE with the bad GITA chip onboard




the obvious fix is to replace the bad GTIA (CO14889) with a good one, but the GTIA is soldered to the board on these models which makes is hard to remove and replace.

here is a hack by adding a 74LS175 Chip you can fix the Bad GTIA (This fix was originally designed my Simius from Poland)

Step 1 is to make a small Cut the traces that connects Antic Pins 2,3,5 TO GTIA Pins 18,29,20 (see image below)





Step 2:

- Piggy back the 74LS175 on top of the connecting only Pin 8 (GND) and pin 16 (vcc) Legs
- Connect Pin1 of 74LS175 to pin16 of 74LS175
- PIN 28 OF GTIA (CO14889) to pin 9 of 74LS175
- Pin 18 of GTIA (CO14889) to pin 10 of 74LS175
- Pin 19 of GTIA (CO14889) to pin 15 of 74LS175
- Pin 20 of GTIA (CO14889) to pin 6 of 74LS175
- Pin 2 of Antic (C021698) to pin 12 of 74LS175
- Pin 3 of Antic (C021698) to pin 13 of 74LS175
- Pin 5 of Antic (C021698) to pin 5 of 74LS175





the result is a clear colorful image in GTIA mode




enjoy​