Author: Bill Collins (209-250-52-15.wispnet.net)
Date: 02-18-2010 04:37
It sounds like the sprites (a.k.a. "player-missile" graphics) are not being displayed properly (bullets on defender, wrongly-sized cowboys with mirror image, etc.)
The chip responsible is called TIA (television interface adapter), and is an early model of the ctia and gtia chips in the later 400/800xl atari computers.
You may have a TIA chip that is functioning just a little bit off. I say keep it as is. It's a rare treasure, because it's one-of-a-kind, but if you want to mess around with it, those things are so primitive inside, and you can just replace the TIA chip.
If that doesn't solve it, then suspect ram. If the actual 8bit motorola cpu was malfunctioning, you'd have bigger and worse troubles than just bad sprites.
Here's the simplest solution of all: find a scratched up plastic 2600 with a black case, remove the guts and put them into your pretty wooden case one! :) Yeah, now that's ingenuity.