Atari 2600 Controller Problem

[BrokenFlight]

I got a small 2600 today, possibly the Junior, although it doesn't say that anywhere on it, or the box. (I expect you can tell I don't know anything about Atari consoles)

It works fine except for the action button. I've tried different controllers, and I've tried those controllers on other consoles. But the action button doesn't work with any of them on the 2600, despite being working controllers.

I've cleaned the pins on the controller port and I've checked the solder points. All I can think of is maybe a chip is fried. What can I do about it, besides spending months looking for another one?

[almostgotthemall]

Most likely the RIOT chip is bad. Unfortunately on the Atari Juniors, they are soldered right to the board making a change-out difficult.

It still can be done(de-solder and remove), but can be a big head-ache. Especially with those older boards.

Of course this also means you are assumed to have a working one on hand to swap in.

Here is a handy link(not sure who wrote it, but it is really good!) to a pin-out diagram of the RIOT if you want to test it while it is still on the board:
LINK (http://tripoint.org/kevtris/2600/2600schemo.html)