Jump to content

Quick question on chip A5 pin 11 on a 5200


Recommended Posts


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 by thomas3120
Link to comment
Share on other sites

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.

  • Like 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Create New...