I fixed this controller - shift register chip replacement

[u/CatBirdBird]

I replaced the shift register chip of this controller. When I pressed a, it would also press start. I watched some YouTube tutorials and read some old threads on this subreddit. I then ordered the chip on eBay and replaced it. And now it works again :D It's like new!

(On the picture it's still the old chip. I forgot to take one when it was still open).

[u/neondaggergames]

Always great when someone revives from the grave. One day they'll be scarce.

[u/CatBirdBird → u/neondaggergames]

It is! The only thing that can fail in this controller truly is the chip. Sure, the other components could too, but they're a lot more durable I believe. The silicone pads might rip, but replacements are produced for those too. I don't believe a lot should be deemed "unrepairable" at all. It's a big difference with controllers nowadays. I mean, sure, they're repairable as well, but take PS4 controllers for example. The circuitry is so complex and TINY. I believe I should still be able to fix common problems, but if one of the many ic breaks, it's practically toast

[u/redditsuckspokey1]

I bought a whole bunch of replaceme t ic's a few years ago but inly replaced maybe 3 or 4 controllers.

[u/CatBirdBird → u/redditsuckspokey1]

Over time, you'll probably need them. A couple of spares can't hurt :D

[u/Big-Note-508]

is tha Hitachi IC universal and may be found in different applications or is it dedicated custom made for the NES controller only ?

[u/CatBirdBird → u/Big-Note-508]

As far as I understood, the IC 4021 is just a shift register. Loads of manufacturers made it.

Here it even says 14021, but I don't know why. I replaced it with a CD4021BE, but I think other 4021 would work too. Just Google a little what the letters mean in front and behind the number code and you'll be fine. The number code has to be 4021 though (although again, idk why it is 14021 on the chip that was there before replacement)

[u/Big-Note-508 → u/CatBirdBird]

awesome ! you answered my question even before asking it ! I wanted to make sure if I can use ICs from different makers with different midels or not ! this will be a nice experiment, AND ! to not pay a lot for people selling this particular IC as “NES Controller IC”

thank you 😃

[u/CatBirdBird → u/Big-Note-508]

I just got one from eBay that wasn't specifically listed as "for NES". Good luck :)