Korg N1 Synth Repair

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

Tweaking the Action on a Roland FD-8 Hi-hat Pedal

Ever since I bought my Roland TD-3SW v-drum kit, I’ve found the included FD-8 hi-hat pedal to be a major annoyance. The problem is that I would practically have to stand on the pedal in order to get the hi-hat closed sound. Adjusting it according to the instructions in the manual didn’t help. I basically lived with it this way until my son recently wanted to start using my drum kit, and couldn’t apply enough force to the FD-8. It was time to fix the problem.

I googled around and found a few fixes, notably this discussion on vdrums.com: FD-8 Hi-hat Controller Pedal – Notes on Improving Volume and Feel. However, I felt that the fix described in the thread seemed too hacky for my tastes. Finally, I found this video on YouTube by a brilliant German guy: How to fix a Roland FD-8 hihat pedal. I decided to try his method, and it worked great! My pedal now has action a lot more like a real hi-hat pedal; you don’t have to mash it down hard to get the “closed” sound. I’ve modified the procedure a little, and have documented it below:

Step 1: Remove screws

In the YouTube video, Marcel practically tears down the entire FD-8. Actually, you don’t really have to disassemble everything. All you need to do is get access to the problem parts. Remove only the screws pictured in the photo below from the bottom of the pedal:


This will allow you to separate the front plastic cover from the metal bottom. The bottom metal plate has a resistor attached to a small PCB via a ribbon cable, which is attached to the 1/4″ TRS jack. This is what the resistor looks like:


There is a rubber foot (show in a photo below), which presses along the resistor in order to tell your drum’s brain box the position of the pedal. The problem is that the rubber foot doesn’t press hard enough against the section that indicates hi-hat closed (low resistance), near where the ribbon cable connects.

When you open the case, the ribbon cable will be attached to the grey clip pictured below:


To release the ribbon cable, simply pull upwards on the grey part of the clip until it stops. Then the ribbon will easily slide out of the slot. The rubber foot is attached to the underside of the plastic cover:


The problem is that the rubber foot is extremely stiff, and doesn’t bend as easily as it should. To remove it, gently rock it back and forth while pulling upwards. In the video, Marcel sprays silicone lube on it to loosen it up, but mine wasn’t that tight.

The method shown in the video is to soften up the rubber foot by thoroughly coating it with petroleum jelly and letting it sit in a warm place overnight. Since petroleum jelly eats rubber, I decided to apply it only on the part that affects the flex action, and not on the contact surface:


In particular, notice how I avoided applying petroleum jelly to the narrow protruding ridge. This keeps it from softening the ridge, which we want to remain hard, to maximize the pressure and lessen wear.

I left the rubber foot on top of my cable TV set top box (a consistent heat source) overnight. The next morning, the rubber was considerably softer, and I could tell that it was taking a lot less force to flex it. Again, here’s where I deviate from Marcel’s video. He initially applies the petroleum jelly a lot thicker than I did, and says to wipe it off after the rubber softens, leaving a layer that’s approximately as thick as what I applied in my photos above. Instead, I wiped the petroleum jelly residue completely off with a paper towel. I figured that some of it would still be soaked into the rubber, and that would be enough. Better than having it eat through the rubber until it turns to mush.

Reassembly of the pedal is just the reverse of the dis-assembly steps. When re-inserting the ribbon cable into the gray connector, make sure the gray connector is pulled up while inserting the ribbon cable, and then press it down to lock the cable in place. Also, be sure that the metal tongue pictured below has a layer of silicone grease on it:


Mine still had enough lube on it from the factory, so I didn’t apply any extra. The rubber foot slides against this metal tongue when you press the pedal, so if it isn’t lubed properly, the pedal may need extra pressure. DO NOT use petroleum jelly here, because it will slowly melt the foot, and probably turn it into mush over time. Silicone lube, on the other hand, does not react with rubber. You can get small quantities of silicone grease in most auto parts stores.. it’s used on the rubber bits of brake parts. Also, you can buy it pool supply stores, or at a hardware store. This cheap stuff at Home Depot should work OK: Silicone Faucet Grease.

My pedals has great action now! I’m not sure if it will harden up in a few months, but the hack is easy and I’d rather play the hack on the conservative side. An alternative hack would be to drill holes along the side of the rubber foot, thus lessening its tension. I was originally going to do this, and it turns out someone on vdrums.com successfully did it (see the the 2nd to last post on this page), but in the end, I decided to first try the petroleum jelly method, since it was less invasive. Thanks again to Marcel (vdrumtips).

Ktone Travel Electric Guitar Review

I’ve been looking for a compact guitar to take with me on road trips, camping, and to play when I’m killing time waiting for my kids at their various lessons in my car. After much research on the Internet, I narrowed it down to either the Washburn Rover or the Hofner Shorty. The Rover looks like a great buy at $125. It gets great reviews, and comes with a very nice soft shell case. For $119, the Shorty, on the other hand, only comes with a cheap gig bag. I was really itching to get the Rover, but after pondering it for a long time, decided that an electric guitar was more appropriate because: 1) it will hold up better in heat/cold/humidity sitting in my car on road trips and 2) it can be played silently in hotel rooms without bothering the rest of the family.

While searching for a good price on the Hofner Shorty, I came across a much cheaper knockoff on eBay – the Ktone Travel Electric Guitar. It looks so identical to the Shorty that many people have hypothesized that they’re made in the same factory. At $69.99 including shipping, it’s $50 cheaper than the Shorty – so much cheaper that my interest was piqued. The Ktone got good reviews at Ultimate-Guitar and some other discussion sites. It turns out that there are several clones of the Shorty in the wild, if you search long enough.

Planet-Z posted a scathing review of the Ktone, complete with photos and a video. The guitar that .. reviewed was a disaster, with loose/unusable tone pot, mismatched wood on the neck, and terrible fretwork.That put me off so much that I was ready to buy a real Hofner Shorty, until I read a comment on the Planet-Z review from someone who bought a real Hofner Shorty, and found it to also be of bad quality. Unfortunately, none of the stores near me have Shortys for me to try out, so I decided to just take the plunge and try the Ktone first, since it has a 30 day money back guarantee (minus shipping charges).

I bought the Ktone Travel Electric Guitar from eBay seller kukufashion. Interestingly, my Paypal receipt showed the recipient as none other than Ktone Corp.!

The guitar comes with a crappy gig bag that looks identical to the Shorty’s and a crappy guitar cable that’s basically a thowaway.

When first opened up the package, I had mixed feelings. The color was metallic blue like the Shorty, unlike the baby blue pictured in the eBay listing. The neck on mine didn’t have an awful looking join @ the headstock like the one that Planet-Z got. Instead, it had some strange colored grain at the other end, and what looks like melted polyurethane. The strange grain is actually growing on me.. kind of like curly maple.

The body’s finish looked decent, and the controls were all installed properly and had smooth action. Thankfully, mine didn’t have the poorly seated frets with sharp ends like Planet-Z’s copy, but although it’s playable, the frets are in dire need of leveling and polishing. The guitar looks like a Hofner Shorty factory reject. Except for the body, the finish work is horrible. The back of the neck has sanding marks, there are various dents and scrapes all over the place, and even the bridge has cosmetic defects. However, I was thinking most of the defects were cosmetic, and what do you expect for $70?

I tuned it up and plugged it in to my amp. The first thing I noticed was that the guitar cable wasn’t clicking in properly to the output jack. It worked fine, but the cable could get tugged out too easily.

The output jack felt like it wasn’t engaging my guitar cable properly, so I took it out to have a look. Amazing… they used such a low grade connector that it didn’t even engage properly with the groove in the 1/4″ TRS plug.
(Notice the extremely thin wiring). OK, not a big deal, and I can always replace the jack easily and cheaply.

The setup of the guitar was terrible, but I’m used to that, even with fancy guitars, so I thought it wasn’t a big deal. The first thing I did was check the neck relief. It wasn’t too bad, so I didn’t adjust the truss rod. Next, I lowered the action. The bridge has so much wiggle in it, and the screws were already screwed in so far that I almost ran out of adjustment lowering the action. Luckily, I was able to get it to a comfortable playing height when I lowered it down to its limit. Not a good sign. I can lower it a bit more by shimming the tailpiece. The slots in the bolts are too big, so the whole bridge/tailpiece tilts up a bit. The frets on the low E and A string need to be leveled a bit past the 14th fret.. there is a lot of buzz there, so I had to raise the action slightly to compensate.

It wasn’t until I started trying to adjust the intonation that I found out what a disaster the guitar really is. The intonation on the low E string was a full 12 cents sharp! No wonder the guitar was impossible to tune! I’ve never gotten a guitar with intonation that far off. First, I tried to adjust the low E string’s saddle, but even when I adjusted it as long as it would go, it was still 12 cents sharp! I was thinking that it was time to pack it up to return to Ktone but then I realized that there are also screws that move the whole bridge backwards. After fiddling with the screws and test the intonation over and over, I finally got it into decent adjustment .. just barely.. to get the low E intonation correct, I had to set the strings to the maximum length.. both the saddle adjustment screw and the tailpiece adjustment screw maxed out. My adjustments lengthened the string by …” Whoever designed the guitar didn’t measure the length of the strings properly. Unfortunately, with the tailpiece adjusted to maximum string length, the G string’s intonation goes flat by 6 cents even when its saddle is adjusted to minimum length. I can’t adjust the tailpiece, because then the low E will go sharp. If I could flip the saddle around, like they way the top 3 strings are, I could shorten the string some more, but the saddle pieces aren’t removable. I am just going to have to live with the G string 6 cents off. Or I could split the difference by making the A & E strings a bit sharp.

One thing that also signals that something is wrong is that the harmonic @ the 12th fret occurs not exactly on top of the 12th fret, but a few mm past it. Something is definitely wrong w/ the positions of the frets on the neck. Despite these issues, after my 2hrs of adjusting the intonation, it sounds a lot better. While the intonation isn’t perfect, it’s acceptable to my ears, especially for a cheap guitar that I’m going to be tossing in the car and taking to the beach. It’s inexpensive enough that I’m not going to cry if it gets stolen or damaged.

After playing with the tuning for a while, I found that the guitar always sounded out of tune, even when I used my Peterson Strobotuner. Something must be wrong with the intonation, I thought.

The single bridge humbucking pickup is pedestrian. It’s not very hot, and the tone is a bit thin, but I was surprised how much effect the tone knob has … makes sound passable. I’ll probably replace it with something better in the future, if I can tolerate the guitar.

The gig bag is cheap, but it doesn’t look any worse than the one that comes with the Shorty. What I hate about gig bags, is that they don’t protect the tuners, so the tuning is always way off when you take the guitar out to play.

So at $69.99 is the Ktone Travel Electric Guitar a good buy? Just barely. If I didn’t have to pay 2-way shipping to return it, I probably would have just returned it. Even if the Shorty has issues, there’s no way that it could possibly be as shoddily built as the Ktone.

Anyway, it serves the purpose I bought it for… a small, light, portable guitar that I can take everwhere and not have to worry about getting ruined or stolen. But I think you should avoid this piece of shit like the plague!