Atari 2600 No video

[BedTimeFun]

So I have been working on a Atari 2600 I have done the cap kit and the RF upgrade. I get a perfect image for a little bit then fads to dark. After have on a little longer the screen gets messed up. After that I loose the image all together but  still have sound(sound is scratchy). I have pulled the chips to try and reset them. At this point I am at a lose. Does any one have any ideas what to try next?

 

Thanks

[Resto Ron]

Which console is it? light or heavy 6, 4 woody, Vader? Which AV mod kit did you use? Need more info.

[Jason_Atari]

I had a similar problem that turned out to be a dodgy power supply.

[BedTimeFun]

I have a 4woody. The power supply works on other Atari's that I have. The mod kit was from vintage gaming and more.

[Resto Ron]

What kind of TV? Old CRT? Newer LCD? with the mod you used there might well be an issue with the signal being too hot. That is why many "updated" mods include an additional resistor to the V-out. The symptoms you described could be because of this. See the pic below. Look at the resistor between the GND and V-OUT. 

 

[BedTimeFun]

I am using a LCD tv. I see you have another resitor across the audio as well. Is that necessary? Thanks for the help.

[ChildOfCv]

Are you absolutely sure you installed the caps in the right direction?  A backwards cap becomes a huge load on the board, and even seasoned veterans have screwed one up.  You should also make sure you measure +5V and GND at the AV mod board.

[+-^CrossBow^-]

11 hours ago, Resto Ron said:

What kind of TV? Old CRT? Newer LCD? with the mod you used there might well be an issue with the signal being too hot. That is why many "updated" mods include an additional resistor to the V-out. The symptoms you described could be because of this. See the pic below. Look at the resistor between the GND and V-OUT. 

 

The irony here, is that when used with many modern LCD displays, that 75Ω across the gnd and video out will cause the image to be dark and dull. Remove it and the image looks much better on modern displays. I've encountered this several times on 7800s with this installed sent to me to remove it and replace with a UAV.

 

[ChildOfCv]

75 between out and ground shouldn't be there in the first place.  It should be in series with the out to video.

[BedTimeFun]

OK so I decided to change it back to the standard RF setup. When I turned it on I had a image played a game but the image was very staticky. Left it on then lost everything again. I tried a different RF cable no change. I also put a different TIA chip no change. I have uploaded an image the best that I can get. This is in a dark room. If I turn on the lights I can not see the lighter images. After about 2 minutes I lose everything. After it cools down it turns on again.

Hope someone has an idea hate to scrap it. Thanks for the Help so far.

[Resto Ron]

 I have had similar issues that I have traced back to the inductors just before the video out went into the RF can. The 2600 field service manual is floating around I suggest you download it and look at your board's revision and use the schematic to find the inductors and as the picture starts to degrade squeeze one inductor at a time. If the pic starts to clear up some you have found the issue. Check the solder joint if it is good replace the part. As for things getting hot I would use a can of air upside down and spray the part that is getting hot this will make the part cold and if the pic clears up you, again, have the issue.