Strange interference type issue with some homebrews/hacks.

[jwelsh]

Hey everyone.  Had a quick question for those of you familiar with Hardware because I really am not. i have a video issue with only certain homebrews and hacks. Original release 2600 games play fine, all 85 or so i own. It doesn't happen every time with the effected games, and when it does happen usually taking the game out and reinserting it once or up to 3 times will make the issue go away. could this be a power issue? Capacitors or something inside the system failing? Or simply just RF interference of some kind? I'm using a light sixer on a CRT through RF. I'll post a picture of one of the affected games and then a couple of pictures of regular games playing fine. thanks alot everyone.

[AtariLeaf]

This has come up before 

 

I've noticed it with games like ladybug, Space Rocks and draconian. It's something about the additional hardware in some of these games. What's really odd is I was getting interference on A/V modded systems too

 

[jwelsh]

Ah so it is some type of interference. im okay with that. as long as my systems not dying. whats funny is my copies of draconian and space rocks are perfectly fine. I don't own ladybug yet however. all of my games that use melody/additional hardware are fine. the only games from atariage i own that have this issue are alligator people, and toyshop trouble. i have a few hacks from other vendors that have the same problem.  seem to use standard pcbs. strange stuff. should probably pay someone for an AV mod and Recap soon either way.  Thanks for the reply Atarileaf.

Edited November 8, 2019 by jwelsh

[AtariLeaf]

I found the problem worst on 4 switch systems like vader's although it shows up in certain games on all models. I just turn the brightness down and I dont notice it

[RamrodHare]

I added a ferrite core and use a coax adapter instead of a switch box and all my games play great, with extremely good picture quality on my 2600 JR.  I composite modded 3 different 4 switch models (Vader's seem to be the worst) and never got the kind of picture quality I expected, even with different types of mods.                             The UAV board was the mod I always wanted to try, but I never had the extra cash. It's got great reviews and I intend to grab one. I just have to get my hands on another 2600 first.                                                                      Try the ferrite core before anything else, they are cheap and work like magic when it comes to cleaning up the interference. If you have some old USB cables laying around, chances are you might have one you can pull a core from. I got mine from an old Sony cable. It had a two-piece core with a nice clamp on plastic shell.

 

[Thomas Jentzsch]

Yup! When using RF, a better shielded cable can help a lot.

[AtariLeaf]

All these suggestions are true but the issue still remains that even when all these precautions are taken, it's a matter of some homebrews still showing some type of interference on systems that otherwise have as perfect a picture as RF allows. As I mentioned, I still get it even on an A/V modded Vader so it's not even RF interference. It can't be. Different systems, power supplies, high quality cables, replacing caps, voltage regulators, etc - all things I've tried over the years to no avail. 

 

I've suspected it may be electrical but even taking my system to friends homes and even local game stores netted the same results there

Edited November 8, 2019 by AtariLeaf

[Rom Collector]

A/V modded systems can still be susceptible to RF interference. 

[AtariLeaf]

50 minutes ago, Rom Collector said:

A/V modded systems can still be susceptible to RF interference. 

Interesting

 I dont understand the technical side so I'm assuming there is some kind of bleed through to the audio/video portion of the mod?

[atarifan88]

I just play them on a FB9 and NEVER get any interference... ?