thomas3120 Posted January 9, 2022 Share Posted January 9, 2022 (edited) Hello, Just received an Atari 5200 which is in excellent shape including mainboard. I'm planning on doing the UAV mod to it. RF shields were in place and appears that no modifications have been done. I noticed chip A5 (GTIA)? had pin 11 lifted. Was wondering if this is something Atari did at factory. It's a 2 port model C021376 REV. 1 Here is the picture: Edited January 9, 2022 by thomas3120 Quote Link to comment Share on other sites More sharing options...
+x=usr(1536) Posted January 9, 2022 Share Posted January 9, 2022 Yep, that's a normal factory modification on a 2-port. 1 Quote Link to comment Share on other sites More sharing options...
thomas3120 Posted January 10, 2022 Author Share Posted January 10, 2022 On 1/9/2022 at 3:08 PM, x=usr(1536) said: Yep, that's a normal factory modification on a 2-port. Thanks for the reply! Just wanted to make sure. Quote Link to comment Share on other sites More sharing options...
+-^CrossBow^- Posted January 10, 2022 Share Posted January 10, 2022 I've seen that several times on 2 port units, but I've also seen it inserted with the rest of the pins on some 2 port units also and not seen any differences in behavior either way. Quote Link to comment Share on other sites More sharing options...
+Stephen Posted January 11, 2022 Share Posted January 11, 2022 I believe that pin is "Trigger 3". On the 8-bit computers, the GTIA uses 3 of the 4 trigger lines as inputs, for the Start, Select, and Option keys. The 4th trigger is an output, and makes the (annoying as hell IMHO) keyclick noise. It can also be used to create a 4th digital channel for volume only music. If you've ever played the game Night Mission Pinball, all the sounds are created with the GTIA. I'm not sure why it would not be used on the 5200. 1 Quote Link to comment Share on other sites More sharing options...
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