Atari 2600 - screen jumps all over the place.

I have an Atari 2600 that has trouble running games. If I run Donkey Kong when DK rolls a barrel they don't go any lower than the top level. It makes a noise like I jump over the barrel but I am no where near it. I took some video of space invader since this game really has issues. I did clean the carts and cart slot but it didn't seem to do the trick.

https://www.youtube.com/watch?v=LDwnL2x5swc&feature=youtu.be

Forgot to mention that both games were tested in another 2600 and both game ran fine.

 

Most 2600 has socketed chips. Open them up and check for creeping chips, reseat if needed. Also check for capacitor. It's got only 2 or 3 but if they are failing it could be allowing excess ripple from the power circuit to leak through and cause unstable operation.

For some reason I am thinking the problem could be in the main CPU, the 6507. The RIOT chip (usually between the CPU and TIA) has very little to do with video as it mostly handled controller and offered some RAM (score keeping for example). TIA (usually furthest from cart slot, closest to RF modulator) is another chip that could be a problem. If you have another 2600 to take apart, try swapping the main CPU and see if that clears up the issue.

 

Thank you I'll be sure to check that stuff out. I reseated all the socketed chips and got the same results so I'll be replacing the caps next. There is a big axial cap 2200uf 16v I will start with that one first. Taking to other one apart to swap the chips in a bit.