Certain cartridges cause static on screen

[rednakes1]

I just bought a 4-switch woody console recently and noticed that certain cartridges cause picture static or fuzziness whereas others don't have any problem.

 

For example:

 

- if I put in my Space Invaders or Ms. Pacman or Sea Quest cart, the picture is fine.

 

- If I run the Harmony cartridge there are vertical blue-ish dotted lines going down different areas of the screen, for every game. See the attached photo of Space Invaders on the Harmony.

 

- If I run the Asteroids cartridge, there are horizontal fuzzy lines going through the "Copyright 1991 Atari, Inc." intro screen and near the bottom, but rest of the image is fine. See the attached photo.

 

 

This problem does NOT happen with the same games on my Atari Jr. or the ColecoVision Expansion Module 1. I've cleaned out the cartridge slot and the cartridges but this doesn't help. I've changed the cable and also used an AV-to-coax adaptor but still no change.

 

I'm wondering what the problem might be? Bad cartridge slot?? I'm also using RF -- Would an AV mod resolve this issue at all (it's cart-specific though)?

[rednakes1]

Ugh.... never mind! I realized the problem. I had removed the metal shield that covers the main chips when I had opened my Atari earlier, and then forgot to put it back on. It makes a huge difference... looks like it blocks the RF interference.

[Thomas Jentzsch]

Yup, also a better shielded TV cable helps (thicker and with Ferrite beads).