I have been unloading most of my pre-crash systems and games, and the 5200 is next on the list.
The fire buttons do not reliably work on the controller that I have that is in the best condition (the other two have issues with the pots). A seerval years ago, I replaced the flex circuit with one of the gold plated ones from Best. By adding foil dots, I had a working controller. Then the system proceeded to gather dust....
Fast forward.... the fire buttons no longer reliably work. I tried replacing the foil dots, and that did not work. Also, one of the pots had failed, so I had to transfer the flex circuit to another controller.
At this point, start, pause, reset and the key pad work reliability and the stick works fine... well at least as good as a 5200 controller will work. Still a no go with the fire buttons. By "no longer reliably, I mean that they seem to work on Berserk, but fail in most other games. This problem was reproducible on another console, so I don't think it is a console issue.
Any suggestions on what I might be missing? My thought is one of the traces on the flex circuit is broken. I do not want to invest in all gold dot parts from Best. I'd do that if I was planing to keep the system, but it doesn't make sense when unloading the games and the system.
Thanks in advance.