I have a heavy sixer that has one paddle input not working. I have tried multiple paddles and all the paddles work in controller port 2, controller port 1 has the issue. I have tested the circuit for continuity and checked the resistor and cap values which all check out. I even swapped the TIA which didn't change anything. The circuit doesn't seem complex, so I am wracking my brain trying to think of what to check next. Any ideas would be greatly appreciated.