I have a Korg N1 synth, which I’ve had for many years. Recently, it started having strange symptoms: after warming up for several minutes, the audio would get slightly distorted, but only on certain notes. The effect was rather subtle, but enough to drive my wife absolutely bonkers.
First, I tried to isolate the problem. I tried headphones, connected to the jack on the front left of the keyboard, to rule out my amp. The distortion didn’t go away. Next, I compared the output from the rear audio jack to the headphone, and the distortion sounded exactly the same.
I first tried google, to find out if this was a common problem. It turns out that the N1 wasn’t particularly popular, so there wasn’t much info on problems/repairs, not even teardown photos.
OK, time to take it apart. I first took the screws off the wood side panels, and removed the metal cover on the front, under the keys. Totally the wrong approach. Upon looking at it more closely, I noticed that the bottom is hinged. All you have to do is take out the big philips screws, and then it flips open.
Once I had access to the inside, I looked/smelled for any burned/damaged parts, loose wires, and bad solder joints. Nothing looked amiss. Another thing that’s a common failure point in aged electronics is aged electrolytic capacitors. They often go bad. The most obvious clue is that the tops will bulge up or burst open. I couldn’t see any that looked obviously bad, so I started touching the tops of the SMT electrolytics to feel if any of them were bulging. I found one that had an almost imperceptible bulge on top. It’s in the photo below:

The bulge is so slight, you can’t even see it in the photo above, but I could just barely feel it. Surely, this wasn’t the bad component? Since I couldn’t find anything else wrong, I decided to try replacing it.
At first, I was going to try to remove it w/ a hot air gun, but it’s so big, and close to other components, that I decided that was too risky. I searched the Internet again, and someone suggested just cutting the can in half w/ some cutters, and then yanking out the rest. It turned out to be an easy and safe method. And, it left two short protruding wires attached to the circuit board, which made it easier to solder in a new cap. (Sorry, I should have taken photos, but forgot).
Anyway, here’s what it looks like w/ the replacement soldered in place:

I was extremely skeptical that replacing this capacitor would fix the distortion, but amazingly, when I turned it on, and left it for an hour, the problem was gone! It’s been over a month now, and there is no more distortion, no matter how long it’s turned on. Amazing.
Below is a full photo gallery of my teardown:
Direct link to Google Photos: https://photos.app.goo.gl/VwxPwYw8nxvgwx8Q9
Nice pics of the inside of a Korg N1. While you had it apart, did you notice if there was a battery to keep the memory intact? I’ve had my N1 and N5ex for nearly 20 years, and I’m wondering if I need to worry about the memory failing because of a battery failing due to age. Also, they are sometimes stored in very cold temperatures and I wouldn’t want to subject them to sub freezing temperatures if there is a battery involved. Any help would be very helpful. Thanks, in advance.
I think any settings are stored in flash memory. There are no batteries inside.
hey I have a request, don’t know if you have other pictures that might give me what I need or if you’d be willing to open this thing back up to get one. I just had a repair done but we noticed we were missing one more capacitor and I have no idea what size it is as I can’t find it. The others two I did were replacements of ones I found in the unit or were still attached but damaged. Although you have good quality pics on your post, of course the one spot i need to read is too dimly lit to see what the markings on this capacitor are.https://mail44.calgah.com/-.._._.–.._1420751600/webmail/server/download.php?sid=wm-679266efd1d61180612495&class=attachment&fullpath=mshay%40sargentappliance.com%2FINBOX%2F25768%2F1.2&resize=1&width=100&height=100&crop=50%25
Sorry, but it’s a huge job to open it up, and I don’t know when I will find the time. I can’t even figure out what you’re looking for from that tiny photo you sent. Can you send a link to my photo of the area? BTW, you can buy a copy of the service manual online, and it will have the full schematics plus info that might help in getting your unit working https://www.partsisparts.net/catalog/korg-service-manual-n1-n5. If you do manage to get a hold of a copy, I’d appreciate if you could email it to me to share w/ others.