This has gotten really odd so I figure this is the best place to get some help. My Atari paddles were jittery at first, and I followed the instructions to clean them. After cleaning them, they were still jittery. I cleaned them again, and the issue persisted. To test if it was a broken pot, I modded a new one from Radio Shack onto one of the controllers, which also didn't change anything.
I have a spare Flashback 4, so I tested the controllers on that. Both of the paddles played very smoothly, almost like new. And yet, when I plugged them into the actual system, they seemed broken. I noticed that the pins on the Flashback seemed smaller, so I tried to use the controllers with a serial port adapter with the same size pins, but it didn't work either. I get that I could just buy another pair, but the controllers aren't actually broken, so I don't think I should. Plus, I'm not sure buying another pair of paddle controllers would solve the problem. If it helps, the paddles are (2nd?) generation, the kind were the shaft of the pot is a lighter color. My 2600 is a Vader.
Ideas? I'm pretty stuck at the moment 