TVG Repair: NES Controller IC Replacement

Back when I was thrifting regularly I found NES controllers quite frequently, so I would pick them up for, at the very least, tradable assets. NES controllers were designed and built to last forever, or so it seemed until I found, ironically, an NES dog bone controller with actual dog chew marks on it. I originally figured something inside of the controller had been severed, or maybe the cable was snapped internally, so I went to work testing a few theories I had. Since the dog bone NES controllers have cables that detach from the internal board I swapped them around with a few other dog bone controllers I have, which quickly debunked any bad cable theory.

I continued to painstakingly check over the board for broken traces or cracks, of which there were none. The only thing I could think of was that maybe the shift register IC had gone bad, so I took one out of a regular NES controller and soldered it into the chewed up dog bone controller. That’s all it took! The controller worked flawlessly once the IC was swapped out. I did try the IC in the rectangle controller and now it too was completely dead. I found it odd that the IC was dead, as it showed no signs of damage be it physical or liquid. For years that poor controller that gave its brain for the greater good to bring back a chewed up dog bone controller has sat in a box, and weighed heavily on my mind, so I decided it was time to bring the poor little thing back to life.

As I was purchasing some other electronics parts I decided to check the website I was purchasing from, Tayda Electronics, for the 4021 Shift Register I was needing, and much to my joy they have them for 37 cents. Once my purchase had come in I was excited to bring this controller back to life. Sure, it’s a normal, abundant NES controller, but this one is kind of a hero in my eyes, as it gave its brain to save a dog bone controller. From soldering in the new IC to testing the controller the whole process only took a minute or two, and the controller now works perfectly.



I’m still not sure what made the original IC fail in the dog bone controller as it showed no signs of damage, but the controller was chewed up, so I’ll just consider the mystery solved. I’m also not sure how often NES controllers have their ICs go bad on them, whether randomly or through genuine damage. Regardless I’m pretty happy to say that a 37 cent part and a few minutes worth of work brought it back to life. Again, I know NES controllers are abundant, but I hope that not too many of them have been thrown away or destroyed due to what is a fairly simple repair. After all, it was through these controllers we all once went on some of the greatest adventures of our lives, and maybe even still through these controllers there are great adventures yet to come.

Posted November 22nd, 2021

About the author

Samuel Floyd first fell into video gaming with the Atari the mid-90s! Always late into the system wars, Samuel enjoys that as he acquires them when they're cheap and the hot titles of yesteryear are bountiful. Samuel loves RPGs, his favorite being Crystalis for the NES.


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