NES Advantage - A button does everything

Hey all -

I recently picked up a NES Advantage that doesn't seem good for anything (yet). I figured it would need some cleaning, however the surprising thing is that the A button seems to press A, Start, and sometimes B. Trying things like Up, Down, Left, Right, and B doesn't work, but we'll see if that changes after the cleaning process is complete.

I've seen threads on other forums from years past of the same thing happening and people going the "well, I will just buy another one" route.

I am going to get this guy cleaned up and maybe reflow some solder before testing again, but I wondered if you guys had experienced this issue. It seems like a potentially semi-common problem with a controller most people don't use anymore. I saw another thread here on assembler that mentioned this might be a potential issue with the clock line to the controller. I suspect that if it has nothing to do with dirty controls or reflow, it has something to do with the controller IC...so this suggestion about the clock line might fit with my assumption.

I'll report back after eliminating the easy variables. All thoughts are welcome.

 

I expect it should not be too difficult to troubleshoot. One of the most common failure point on all controllers is the cord. If two or more wires in the cord short together due to breakage I guess it could lead to something like that. But typically some buttons will just stop working.

I do remember a particular NES controller that behaved wonky and I pinpointed the fault to the chip inside, I just swapped the PCB from another controller that had a broken cord.

 

Sorry for double post but I just remembered I had the same problem once and it was not with a controller but with the console.
Turns out that the Register latch line was faulty on the console.
This line goes to the controller port


On my console the CPU would not output the signal properly, a controller plugged in this console would behave as you described, like every button was pressed at once. If the OUT 0 ( register latch ) is broken in either the cord or in the controller, i believe it could create the problem you are having.

 

Short story - simple fix. Cleaning alone was all that was needed. Continuity to all wires was good from plug to board.

I had a spare 8 bit shift register ready to rock should that have been the problem, but the fix was fortunately a lot less involved.

Now I find myself wanting to shift to mod mode and use microswitches, BUT....other projects first.

Thank you for taking the time to respond, MaxWar.