rednakes1

Yeah I saw that, I'm just hoping it's just a cap, seeing how it was the solution for some of the jailbar issues I've been seeing on the web.

So based on your last paragraph, it's probably a losing battle then.

In that case, I could probably get the radial cap. Even though the holes for the 2200uF axial cap (power and ground) on the Atari board are spaced far apart, I could try to get Ground from another point (i.e. next to the green chiclet cap).

So if this cap is degraded, wouldn't there be AC noise coming into the circuit? Also, I notice I can get an electrolytic radial cap of the same capacitance and voltage at a much cheaper cost (and faster delivery) than the axial type used in the Atari. Would there be any difference in function?

For me it happens on all games with a bright coloured background, or if I turn up the brightness on a black background. I sold a lot of my games but all those had issues too. Eg. For cartridge, off the top of my head, the more obvious ones: Kaboom (green background), Robot Tank, Demon Attack (the flash when I die)

This happens to me with all 7 cartridges of mine (1 is Harmony), with composite AV mod. Also happened when it had RF coax.

Thanks Osgeld. Looks like a lot of trouble though. I notice on the Atari there are only a few of the electrolytic (cylindrical) type capacitors. Those sometimes stop working 100% after some time. What does the huge 2200uF capacitor at the left side of the board do? (EDIT: On the schematic it looks like it is involved with the power switch decoupling) There are two others at 4.7uF.

Here's another one to add to the list. It's a 1970s CRT that had jailbars. Solution was a capacitor replacement. The original cap had lost some of its capacitance over time: http://www.videokarma.org/showthread.php?t=254922 Might be the same issue we're having. I have a multimeter but it has no way to test capacitance...

In what ways could someone fix the issue if the problem occurred on an address line? P.S. Today I also received a set of those green mylar 'chiclet' capacitors in the mail, so I replaced the cap next to the voltage regulator. It had no effect on the picture quality.

What about the plug-in rom socket (cartridge slot)? It has address lines and power/ground pins. I mean I could do some decoupling there but I'd likely be wasting my time. Anything I could check there?

I just tried putting the 0.1uF cap between pin 4 (5V) and pin 2 (ground) of the 6507, and then pin 20 (5V) on the RIOT and an adjacent ground point. No difference

Okay I'll try this tonight if I find time. I'll do pin 20 on the RIOT and pin 4 on the 6507.

Yeah I was worried about the distance of the cap from the chip as well. Do I just need to try the 5V pins, or would the other pins potentially require decoupling?

Sounds like a good plan. I could connect one leg of the cap to ground and the other end to a wire which I can use to probe each pin on the two chips. Would it be sufficient to start with 0.1uF? I have 1uF, 10uF and 100uF caps too but they are electrolytic type.

Okay, so I had some free time tonight and I decided to try out the decoupling capacitors at the TIA. I chose 0.1 uF ceramic caps because I notice on the schematic they're using the same size at the voltage regulator (plus I have several of these on hand; the rest are electrolytic caps which are larger size). So I soldered one cap from TIA pin 20 to ground on the PCB, and another from TIA pin 23 to ground (pin 22). I powered on the Atari, and unfortunately the caps made no difference. Maybe I should try a bigger size next time... No idea. Also, I don't have an oscilloscope and haven't used one in almost twenty years either.

I was just emailing him the other day so I decided to ask him about it after your other post. Regarding the cap, he said: The additional electrolytic cap on the 2600RGB switching regulator board is to prevent radiated EMI. The original RF signal cannot be used if it's not fitted. There is already a large capacitor located on the Atari motherboard, but it's usually too far away to do the job well.

Is this the one by Tim Worthington? I didn't realize till now that it also supports composite. I see that his mod replaces the TIA entirely. I also noticed he put a large capacitor at the voltage regulator to reduce "radiated noise". http://etim.net.au/2600rgb/installation-4switch/

Good idea. There was another user (@hizzy) who also mentioned this, on page 1. Has anyone actually tried this with game consoles and noticed a difference?

Stupid question - On the 4-switch Atari's schematic diagram, why do both pins 20 and 23 of the TIA have a 5V power input, instead of just one of them? I'm wondering if the jailbar issue is caused by noise being introduced by that power going into the TIA. In that case we'd need a proper decoupling capacitor between those inputs and ground. Last month when I was doing my own AV modding and testing, I tried taking out the individual Luma and Chroma output lines one-by-one, and none of them seemed to introduce the jailbars on their own. So it must be something before that, which is why I'm thinking of the above. I got the idea after reading a forum post for the PC Engine / Turbo Grafx (I know it's a far more complex system than an Atari 2600, but it could be a similar problem): http://shmups.system11.org/viewtopic.php?f=6&t=56083 I could probably test this out in a couple weeks, unless someone else with the issue wants to give it a shot. EDIT: link to schematics - https://atariage.com/2600/archives/schematics/index.html

I needed two switches and black dust covers for my Atari 2600, and Sean answered my post right away. Sean had taken the time to remove them from his own Ataris and sold them to me for almost nothing. My Atari is now good as new. A great guy to interact with!

I notice Radar Lock is included. How would you play it on this system when it requires two joysticks to play? The second joystick/button is used for thrust and weapon selection.

What's the size of the portable version compared to a PS Vita? Anyone have both? I can currently run my Atari games on the hacked Vita's Stella emulator but would be nice to have something easier to carry around and with possibly other advantages.

That's a good find. Not sure what it means. The flowchart it refers to is also a bit cryptic to me. Looks like an issue with the address/data lines on the CPU, as someone else had suggested in this thread.

I just sold my Sega Master System last month. I had it for 25 years but couldn't stand the games, aside from a few. I did consider the 3D Glasses and Light Gun but they weren't worth keeping the system for. (I didn't own those peripherals though)

Mine is composite modded, I don't think it will be affected by that, i.e. RF interference effects.