Atari 2600 graphical issues.

[simplyretrogamer]

Hi everyone Hope someone can help me, I am having issues with my 2600 4 Switch PAL, when I boot Asteroids, the game will appear on the screen but has graphical issues (image attached) and sometimes will change colour to dark purple. Games like Pole Position I can hear it but can't see anything on the TV Screen. I was wondering if anyone has had this issue.

 

Steps I've currently done:

Changed the main cap 2200uf 35V and the 4.7uf cap with new ones.

Cleaned the pins on all three chips - Chips are soldered not socketed.

Change regulator to a new one.

 

Thank you in advance.

[juansolo]

Power - Are you using the original PSU or a modern one? If it's a modern one what is it? Check the output of that with a multimeter. Make sure you've got nice stable power going into and coming out of the reg. Make sure the ICs are getting the correct power.

Modulator - Are you using RF? If so it's entirely possible there's a problem in there. Bypass it with a simple composite mod and see if the problem stays or goes. This will help locate the problem.

Bad joints - Cleaning joints won't do anything, you want to reflow them. The ICs will likely be fine. The mechanical connections are where you tend to have trouble. So the power and joystick sockets, the cartridge slot, the ribbon between the boards.

Clean stuff - Grab some IPA and clean your cart slot and your cart edge connectors.

 

Beyond that you'll looking at probing things, which is where things get more difficult/interesting.

[+-^CrossBow^-]

Well, the goofiness you see in the asteroid rocks is actually normal. The rocks flicker and on many modern displays, the signal will result in those rocks looking like they are missing colors in the middle of them with the stripes through them. Has to do with the TV not able to handle the interlacing of the signal properly. As for the Dark purple? Is that while you are playing the game or while you just have it turned on and sitting there like in your picture?

 

If you just have it sitting there and aren't actually playing it, then the color changing is actually normal. That game along with a few others back then, would start to cycle the colors on the game as a form of screen saver protection to prevent burn in on the TV back in the day.

 

Not sure on Pole Position though. Are there any other games that just refuse to play?