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Yamaha TX16W the hidden gem!

When I first heard the Yamaha TX16W sampler back in 2009, I immediately knew it wouldn’t stay in the sub $50 price range for long. The sound was simply outstanding—rich with character, and the low end was astonishingly powerful! This realization hit me during a quiz posted in 2009 on the Harmony Central forum by Paolo Di Nicolantonio. The quiz presented several options, and I was convinced the mysterious sampler was either the Emulator III or one of the high-end Roland models like the S-750 or S-770. When Paolo revealed the TX16W as the answer, I was completely stunned. I couldn’t believe it! Without hesitation, I purchased one, which at that time was for a little more than the cost of shipping.


Paolo Di Nicolantonio

Paolo, by the way, deserves the credit (or blame!) for this discovery. He runs the exceptional Synthmania YouTube channel, which I highly recommend. At the time, I didn’t know Paolo very well. He looked kind of like Paul Sorvino and I didn’t wanted to critique the quiz, I wondered what if he’s a mafioso, and I didn’t want to end up in the river with a pair of cement shoes. (note: previous sentence is an old inside joke from the ole Harmony Central forum… Paolo is not a mafioso, but a synth enthusiast and a great music tutor). After I submitted the quiz with the wrong answer, Paolo kindly messaged me privately with the correct one. Thankfully, I managed to secure one. Nowadays finding a cheap TX16W for $50 is more less a statistic rather than rule. You might have to prepare the amount of cash that is order of magnitude larger.

Here are a few demos from the quiz. Keep in mind these are mp3 quality, you should really hear one in person. Still I hope they impress you as they did me:

  • Synth.mp3 – lush, 3D spacious sound with huge bottom end. Copyright Paolo Di Nicolantonio.
  • Fat Synth.mp3 – another thick stereo synth pad. Copyright Paolo Di Nicolantonio.
  • NewOrder.mp3 – a nice beefy bass. Copyright Paolo Di Nicolantonio.
  • Quadro.mp3 – Retro rave stab showing the beautiful charming character of TX16W. Copyright Paolo Di Nicolantonio.
  • Underwater.mp3 – Crunchy and gritty when transposed low! Copyright Paolo Di Nicolantonio.
  • Resosynth.mp3 – Sweet and juicy filter in action. Copyright Paolo Di Nicolantonio.
  • More audio examples can be heard on Synthmania website in here.

The Character
As opposed to some other 12-bit legends such as the Akai S950 and Roland S-550, the Yamaha TX16W does not darken or tame the sound as the audio is pitched down! This is a crucial point when discussing its character. Rather than becoming duller or less engaging, the sound actually becomes more fascinating as it is pitched down. Examples like Underwater.mp3 and Quadro.mp3 illustrate this beautifully. Instead of losing its edge, the TX16W retains all the sharp transients. But why is this the case?

Let’s start with the Akai S950. When slightly overdriven, its inputs produce a gorgeous overdrive, thanks to its retro PCM converter / electronics, making it perfect for trip-hop and similar styles. However, when you transpose a sample down, the CV signal unfortunately forces the filter to track permanently. No matter how much the filter is opened, the CV overrides and closes it, resulting in a dark, dull sound. All the grit and crunch are lost in the process.

Another example is the Roland S-550, another cult favorite, widely used in early rave and techno tracks. Its “problem” lies in its nearly perfect transposition. When you pitch samples down, they become increasingly round and smooth. This is in stark contrast to the TX16W, which unveils entirely new sonic textures as you lower the pitch. Random samples reveal unexpected patterns and sounds, with harmonics that were originally too high to hear now entering the audio range, preserved rather than smoothed out or filtered away entirely.

And that’s the secret of the TX16W. To quote Acreil from the Gearspace forum, who’s top expert in audio playback of old hardware synths and samplers: “Yamaha (TX16W) uses linear interpolation with 3 fractional bits and (effectively) a 400 kHz sample rate (though it’s actually considerably more complicated than that, and I won’t get into all the details here). This can sound pretty clean if you want it to, but it can also sound extremely nasty if you transpose down a lot—just like all the other AWM models. – It’s mostly the way the samples are transposed. As far as that goes, the TX16W already has a more interesting sound than the Akais.”

The punchy drums
Another fascinating characteristic of the TX16W is the punchiness of its sound when the signal is driven slightly hot into its converters. While this trait is typically associated with the Akai S950, I was completely taken aback when I compared the TX16W to some of the most renowned samplers in this area, such as the E-MU Emax, SP-12, Ensoniq ASR-10, EPS, Roland W-30, Akai S950, S3000XL, MPC 2000XL, MPC 3000, and a few others. In one particularly extensive test involving a sampled breakbeat, I listened with my eyes closed and consistently found the TX16W to be the punchiest. This was surprising, as I never expected it—or at least, I assumed the Emax and S950 would dominate in this regard. Here’s a link to the test—feel free to listen for yourself and draw your own conclusions: Vintage Samplers contest (sound test. comparison)

The secret of its unique sound
As you may know, most hardware and all software samplers use a fixed sample rate and resample data in real-time to transpose the sample. However, some older samplers like Emulator II, Emulator III, Akai S950, Prophet 2000 and Korg DSS-1, employed a “divide by n” technique, which functions like tape playback. In this method, the pitch is altered by changing the speed (or clock), eliminating the need for dithering filters because there is no interpolation—pitch changes occur by directly adjusting the clock speed.

When it comes to the TX16W, things get a bit confusing. It appears to use both techniques to some extent. Let me first quote Magnus Lidström, the author and programmer of the Typhoon, operating system for the Yamaha TX16W:

“The TX16W has a fixed 400 kHz output sample rate and linear interpolation for pitching whole octaves only. It then holds samples for exact pitch within octaves (essentially changing the length of individual sample points). The output filters are pretty sloppy with only 24 dB per octave (18 dB for the individual outputs). Sampling filters are much more impressive with an eighth-order Chebyshev design. Also, the main output DACs are not linear but use a floating-point 16-bit resolution (the individual output DAC, on the other hand, is 12-bit linear).”

Acreil, from the Gearspace forum, provides further insights on this topic:

“It’s super weird and complicated, but great. It generates a variable clock from 25 to 50 kHz and uses that to increment the sample address. The clock is derived from a 400 kHz master clock (essentially the sample rate), so it has a lot of jitter, but unlike a phase accumulator, the period of each succession of 64 (I think) clocks is always constant. So you hear some distortion of the harmonics, but not aliasing per se. Higher and lower octaves are obtained by making the sample address increment larger or smaller, so it sort of decimates the waveform by powers of 2 at higher octaves (the PPG Wave 2 also does this). When the address increment is less than 1 sample, it does linear interpolation with 3 fractional bits. The RX5, TG33, etc., work the same way. The TX16W’s filters are even weirder than that.

The original AWM sample playback engine (used in the TX16W, RX5, RX7, TG33, plus some other stuff that no one cares about) uses what Yamaha called pitch-synchronous sampling. It’s basically what I described earlier in the thread—constraining pitch so that each waveform period is an integer number of samples. At the time, I didn’t realize it, but similar methods were used by Casio, Seiko, and Technics. The sample rate is effectively 400 kHz, generating a clock frequency from 25 to 50 kHz to increment the sample address.

When transposing down, it uses linear interpolation (though it’s quite rough, with up to 3 fractional bits only). When transposing up, it skips samples in powers of 2. Technically, there’s no aliasing, but there are sub-harmonics. Pitch resolution is about 3 cents at any frequency. And it’s got extremely weird time-varying FIR filters, but the effect is rather weak. On the whole, it’s my favorite sample playback engine—both for the sound and because it’s an ingenious technical oddity.”

Upgrades
Due to the large number of online sound banks (I counted a total of over six hundred floppies), including awesome sounding factory disks, I highly recommend installing a FlashFloppy or HxC drive, ideally with an OLED screen (as shown in the image above), again due to huge library it’s much easy to navigate rather than stare at the 3 segment LCD (which I removed and installed an OLED). The main display of TX16W can also be upgraded—in my case, I installed a white-on-black LED screen, which looks great.

One important point to mention is that the TX16W uses a switching power supply, which, as of 2025, needs to be recapped since its components have exceeded their lifespan. I’ve witnessed this firsthand, where at least half a dozen capacitors had dried out.

Lastly, let’s talk about RAM. From the factory, the TX16W comes with 1.5 MB of RAM. Based on my personal experience with my Akai S950 (upgraded to the maximum RAM of 2.25 MB), I would strongly recommend upgrading the TX16W to 3 MB (one expansion module). For more serious work, it’s ideal to have the full 6 MB installed. Since this is a 12-bit sampler, 6 MB is equivalent to having about 9 MB on an Akai S1000, which is sufficient for most use cases. The factory-installed 1.5 MB is adequate for loading factory disks, but for more demanding projects—such as properly sampling a TR-909 or TR-808 kit—at least 3 MB is highly recommended.

Fortunately, there’s a modern solution for RAM expansion. A company called Indigo Audio recently designed an excellent RAM upgrade board (created by Suad Cokljat), shown in the image above. Their expansion is superior to the original, as it draws significantly less current, which helps extend the lifespan of your power supply. The price is also comparable to existing RAM upgrades for the TX16W, making it a great investment.

Finally, the magic number: 3072 kB, or 3 MB, in my TX16W—I’ve been waiting for this moment for so long! Now, I can finally enjoy my MFB-503 sample set and still load a few additional sounds, which was previously impossible. Considering how amazing this sampler sounds, I doubt I’ll stop at 3 MB.

Another important reason I recommended FlashFloppy earlier has to do with saving. Let me give you an example. My MFB-503 set, which I sampled, edited, and programmed on the TX16W,  occupies two floppy disks. This is because the TX uses SD (single density) disk format which is 740 kB. Now imagine saving the fully expanded 6 MB RAM onto floppies. This could take as many as 8-9 disks, depending on the number of programs and samples. At the very least, it would require 8 floppies. This is where FlashFloppy becomes essential.

The image above shows the newly installed 1.5MB expansion. It stands firmly and does not wobble. As of the floppy emulation. For those nostalgic for the ‘vintage’ floppy experience, you can even add a small piezo speaker to emulate the sounds of head movement. FlashFloppy natively supports these classic “clicks” and “zaps,” and I’ve installed one myself for that authentic retro touch.

Operating system
One of the most talked-about aspects of the TX16W is its operating system. Yamaha’s original OS was considered unintuitive and clunky, leading many users to struggle with its workflow. Navigating through the menus required patience and a thorough understanding of its manual, which could be a steep learning curve for beginners.

Fortunately, a third-party operating system called Typhoon 2000 was released later, dramatically improving usability. Typhoon streamlined the interface, making sampling, editing, and playback more straightforward. Many modern enthusiasts recommend using Typhoon for a smoother experience with the TX16W.

Conclusion
Sonically, the TX16W is a true gem! Nothing else sounds quite like it. No other sampler features this unique playback method, and the way harmonics emerge during transposition is pure magic—almost as if it sings on its own. It can proudly and confidently hold its place in your rack alongside any of the big names, like the ASR-10 or the Akai S series.

Library
Let’s not forget the huge library for the TX16W that is available online from various sources. Eventually, I ended up with 630 disk images, which is why the FlashFloppy/Gotek solution is a must. Below is a screenshot of the library I’ve compiled for my Yamaha. Using actual floppy disks for this would be impractical.

Regarding online resources, there’s one important thing to understand: Yamaha uses a (PC) DOS-style disk format. Some of the floppies you find online may be in the form of a folder. To create a disk image from such folders, there’s a great tool called TX16W Floppy Baker, which is available here.

I’m unsure of the legal status of Yamaha’s library, which is why I don’t share my collection. Besides, I built it the same way you can—by downloading zip files, extracting them, selecting the folder content for each “disk,” and sending it to the Floppy Baker. I know it’s a lot of work—I’ve been through it—and after 2–3 days, you’ll have a complete library in .img format. If you’re not keen on building the library yourself, there are other sources that provide precompiled images you can put directly onto a USB stick. However, I can’t guarantee those will include everything I have, or vice versa. Each entry you see below represents one floppy image created using the Floppy Baker utility. Happy disk hunting!

Typhoon OS
If your Yamaha TX16W still uses a floppy drive, you can load Typhoon 2000 from here. However, if you’ve already upgraded your TX16W with a Gotek floppy emulator, I’ve prepared an archive that will save you hours of work. (Typhoon is not originally in .img format, and extra software is typically required to install it, etc.). This archive contains the Typhoon OS converted into a floppy image, along with two configuration files. Place all three files in the root directory of a FAT32-formatted USB stick. You can also edit the FF.CFG file to adjust the speaker loudness or change the display type. Currently, it’s set for an OLED display, but you can change it to a 3-segment LCD if needed. The archive can be downloaded from here.

Demos of a few dozen hardware Reverbs

Far from any scientific or “professional” test, this is just a quick bunch of demos when a reverb is pushed a bit harder, say into the 10 second decay time and only around* -6dB below main track. Don’t use it as a reference because results will vary depending on the recording levels at – take it with a grain of salt. All tracks encoded to FLAC (lossless format). Feel free to share if you find it useful.

Regarding the Akais, both of my units are expanded with their respective FX boards (it is not the same FX board as they are many years apart) and they can be used as a regular effects processors, while Kurzweil has a sampling board which again turns it into an external effects processor (it can do way way more than just a reverb, think of it as Eventide’s little brother). I no longer remember why I recorded two reverbs from PCM-70. I guess I wanted to display it’s less chorusy side of things and more closer to the rest of the bunch.

*yeah, some reverb tails might be a bit off. I actually mixed everything on an analogue mixer during the period of a few days, so probably some are louder than others. Sorry about that!

Bonus:

SY-77 Restoration

LCD Display
What is the name of the ugliest display ever made? It’s the one for SY-77. Looks like some old 80’s calculator lol. Anyway, a friend brought this unit for restoration so I have decided to document the process. I am a proud owner of the TG-77 module version of the SY. It is one of the most powerful hardware digital synthesizers ever made. The only thing with more power released during that era are the Kurzweil K2x00 series, but that’s another topic.

So I have bought a new display to have it installed in the unit. My only fear was, will it work? I did some replacements in the past and have some experience there. Fortunately there is one thing that will help a lot in this task and that is the fact the SY-77 has a display ribbon connector access point on the very back of the PCB boards. Literally right after you lift up the hood (or the bottom plate to be more exact) you will find a display ribbon connector there.

The first task was to buy a ribbon cable and IDC connector (20 pin). I have soldered the cable to the display and crimped the IDC onto the other end carefully taking care for the pin layout. Display ready! But will it work? Quick run to the unit, disconnecting the old ribbon, connecting the new ribbon to have the display connected. And….. It does not work!

Display UPGRADE
My fears came true. The “age” difference between the two displays is simply too big. Display is completely black when powered on, indicating a wrong contrast. Even with the LCD contrast knob turned full counter clockwise, it is still completely black as we can see on the image below.

Back to the bench. Time to install a potentiometer between the positive voltage and LCD contrast voltage supply, turning it until I can get a contrast in some reasonable range.

Desoldered the potentiometer, measured the resistance and looked for the equivalent resistor.

In my case it was 10k. Please do not take any of these values as any sort of reference because the outcome of every display will be different due to different manufacturer specs. Anyway, moved back to the synth, connected the display. And…. It works!

We finally have the letters! Now it’s time to turn on that backlight!

Display UPGRADE 2
The problem with SY-77 is that it supplies super high voltage to the backlight EL foil and we can not use the existing power supply source. So I have decided to borrow some current from the display module to power up the backlight. Of course by using a current limiting resistor. But which value to use?

I briefly connected the LED element and measured 150mA current draw which is too much. Most manufacturers recommend 100mA max for these backlight units. So I have decided to throttle it down a bit to 70-80mA to ensure the long life of this backlight. In my case it was 1.6k ohm. Please do not take any of these values as any sort of reference because the outcome of every display will be different due to different manufacturer specs. Anyway, tested it again, this time with current limiter, and it works!

Finally we have a LED backlight!! Good bye to that crappy EL foil doing nothing, just whining high pitch noise. Running at 75% power should definitely give a 100,000 hours rating. I would never recommend burning a LED element at 100% power, especially for studios that have units powered on 24/7. To make sure I am in the correct brightness “ballpark” I brought my E-MU E5000 as a reference, and sure enough at 75mA the brightness is exactly the same as on SY-77. I guess folks at E-MU were thinking about the longevity of their displays as well because I know both displays can go more.

Here is the finished modification. Two wires and two resistors in the end. Looks simple, but took a lot of R&D. Maybe not the prettiest look but it gets the job done and the display works. Most importantly the contrast knob on the back of the unit now has full range.

Display UPGRADE 3
This is the downside of replacing old displays with the new. They require many modifications. As we can see we had to do two modifications so far in order to work. Soon we will see it requires one more, this time to properly fit into the unit.

After some quick tests I realized that putting the new LCD display was not as easy as expected. The hole (raster) standard has changed a little bit and because of that I had to modify the LCD board and the enclosing plastic cover using the Dremel tool.

Finally it fits, both the holes and the frame which I resized. It would have been very frustrating to go thru all of this – disassembling the unit, modifying the new display, only to learn one can not fit a display in!! Fortunately there is enough space left inside to allow this modification. It seems that the original display was just 2 millimeters smaller in height and had.

Floppy REPAIR
First thing I tested after powering the unit was the floppy. I have inserted one, selected the Format and was greeted with horrible noise of “something gone wrong” type of noise. It was clear the floppy was dead. So I have disassembled it. As expected, the existing rubber band of the floppy is completely disintegrated.

The only thing that was left was some gross looking resin that refused to go down.

Eventually a screwdriver, q tips and some alcohol solved the issue. I would highly recommend 99% alcohol on these tasks. You do not want any water left in here.

New rubber band installed, fingers crossed. What is left to do is to clean the heads of the floppy and to lubricate the mechanism. And I hope the floppy will come back to life.

And it works! Excellent news.

Cleaning
Now it was time to wash the exterior since I have to take apart everything in order to reach the LCD screen. So let’s combine practical with useful. The only proper way to do this is to take a camera snapshot of every board before you remove it, its all connectors and screws. I actually used a graphics marker to mark the position where the screws were located because many of the boards have multiple holes and not all are populated by screws. It is a multi layer design! There are boards on top of other boards. So be very careful with screw and cable management!

And here we are 1 hour later. The unit is disassembled. Three are a total of 6 large PCB boards, plus power supply and display unit.

Another view showing most of the synth now on the floor.

These are all the screws that go into the unit. They are separated by each board to make assembly quick. Because there are so many of them.

First parts being cleaned.

Followed by more washing.

And more washing.

And even more washing.

And a group shower included.

I used compressed air and then a glass cleaning solution to make sure the display bezel and glass are without one single dust from the inside. I hate seeing dust particles in front of the screen! This is my personal obsession so you can ignore this part of the restoration.

Switch replacement
Switches are located on top panel boards. In the case of this unit, these two boards contain switches that have gone bad. Ten switches required to be pressed several times in order to work, while four of them did not work at all and it was only a matter of time when more would fail.

I bought switches from Vintage Synth Parts guy on eBay. He is the best and has switches for all of the synths, most importantly with the proper switch force. It is a force you have to apply to open the switch. If you buy wrong one, the unit will be too ‘clicky’ or too stiff. Hence I buy from this seller as he has replacement switches with correct press-force parameter.

Finally done removing the old switches! Please note, you need a good desoldering tools for this job, especially because there are 70 switches x 4 pins = 280 pins to desolder! That’s a lot of work.

Do not rush as you risk damaging the PCB traces. With that being said I would say these Yamahas have some of the best PCB boards that I have ever worked with. In the images below we can see the fresh new switches installed on both button boards.

Battery replacement and UPGRADE
This is very important part of the process as most of these batteries from the late 80s are reaching their end times (hats off to exceptions). Here is a quick look at voltmeter display. The battery is is running low and no longer provides 3V.

Instead of replacing the battery with the soldered one, I have decided to upgrade the unit install the battery holder instead.

So that whoever will replace that battery in the future will not have to do any soldering. From now on it will be plug and play.

This is where the old battery was located. I have desoldered it and installed a battery holder. From now on the new owner can replace this battery simply by pulling it out with bare hands. No soldering required. Saves a lot of time!

And here we have a new battery installed. Quick measurement shows we finally have the required 3 volts. Success!

Good bye to noisy inverter
This inverter was used to power up the EL foil display. Since our unit no longer uses EL foil but LED to provide the light to the LCD, this inverter is no longer needed. We will remove it because it produces a very high whining tone that can be irritating after a while. On top of that, this interference can also leak into the audio path. So we will remove this inverter.

It is located on the jack board. And should be removed if you upgraded your display to LED. With the inverter removed we can call this project completed!

Putting it all back together
It literally took me one and half hour to put this thing together. There are a lot of boards, a lot of cables and a lot of places where you can screw up. I almost assembled complete unit without alpha dial! That means I would have to disassemble everything again just for that one part and then again assemble it. That would take 3 hours. This is why double check everything! It was of pure luck I realized I didn’t install the alpha dial while being at the first stage so I just had to unscrew 4 screws. So I was lucky. Here is a quick timelapse.

Gathering things together

Display in

Switch board 1 in

Switchboard 2 and alpha dial in

Shield in

Keyboard backbone in

Card reader and interface in

Bender area / end cheek

Audio board in

Left cheek in

Keyboard and second shield in

Transformer and PSU in

DSP board 1 in

DSP board 2 and shield 3 in

Floppy drive in. And we are complete!

The results
Every button can now be operated with the pinky finger. It is a super sensitive now. Alpha dial works perfectly after being cleaned with compresses air, and so do sliders. Visually, the unit looks completely new! As it just came from the store. The new green LED display looks super sexy! By the way, this was one of the filthiest synthesizers I have ever worked with. The display area was so gross that I decided not to post any pictures. I assume this unit was used in live situation before it came to the current owner who decided to send me the unit for refurbishment. For those wondering, how much would job like this cost, below 600 notes there is no way I would do a job like this!

IMPORTANT DISCLAIMER
Please note this is just my personal blog of this particular restoration project. Unfortunately I do not have time to answer to any questions. Although if you understand electronics then you already know everything I did above and how to apply it to your own case. If you don’t understand electronics, please leave it to a competent person to handle electronical device. There are too many factors involved, from potential damage to the unit to the most extreme case – for those who don’t know – electricity kills.

New LED display is too bright? Here’s the fix!

There are a lot of replacement LED displays on the market, however some of them have not been properly configured for some specific synthesizers. For example the stock JHD732-24064C is way too bright when installed in Yamaha SY-77. Not only it will make its life shorter but the backlight is kind of on the light side of the blue, burning too fast IMO. So if you bought and installed a LED replacement LCD for your Yamaha SY-77, TG-77 or SY-99 and noticed it is a little bit too bright, don’t worry. A simple modification is required and you will be all set. I can not confirm or deny that one of the sellers who sells these replacement displays didn’t paid attention to the voltage that supplies the LED element. The fact of the matter is, the LED backlight is set to be driven by 4.7V which is way too much for a LED based element. A classic LED diode is usually set at 3.3V while displays usually go 3.4-3.5V but should not exceed 3.6V. Else the 50,000 hours rating can not be guaranteed. It will be more like 5,000 hours LOL!

It is easy to recognize these JHD732-24064C replacement displays. They come with just a strip cable and no power cable. The power is taken from the logic power supply line. And the value of the provided current limiter on the board is simply too small. If your display is as bight as this, it’s no good:

A friend offered to sell me his TG-77 and as soon as I saw the display brightness in his offer via FB I knew something isn’t right. Since I was looking for a TG-77 anyway, i bought it, but decided to inspect that display – it was way too bright. Unfortunately there is no schematic for this display board, but some visual inspection showed two jumpers on the PCB board that someone enabled. And as soon as I’ve measured 4.7V over the Anode – Cathode I knew we are onto something.

LED backlight full manual control for JHD732-24064C and Newhaven displays
In this article we will create manual control for the LED backlight. That way we will have a control over the brightness of our screen. This will ensure the long life of our LED backlight and also help relief stress from our eyes during late night hours operating on the synth. If you have a Newhaven display, go to the bottom of this article. And please note, this modification applies only to LED based LCD displays and not to the factory installed EL Foil based LCD’s that came on stock Yamaha SY-77, SY-99 and TG-77.

The two wires labeled FROM LCD and TO LED ANODE are actually the two wires that you solder onto location shown in the picture below.

On the back of the LCD unit you will notice two jumpers. Disable the one on the Anode end. That way current can no longer approach the LED and we can install our own current limiter and a potentiometer. Also inspect that the jumper for the Cathode is enabled (connected). While there, solder a wire to the SMD resistor and another wire to the IC’s pin 8. My advice is to buy 1m of ribbon cable and simply take out 2 wires out which will become our “cable”.

You want to apply a hot glue because we are talking SMD components – they don’t like having wires soldered onto them. This is to release the stress from the wire – SMD component junction/solder point which is the weakest point of this circuit now.

You will measure the length of the new “ribbon” wires until they reach the area near the power supply socket. Because that’s where the potentiometer will go.

Now you will drill a hole there.

And install a 1k logarithmic potentiometer with a 47ohm resistor on one of its connected ends.

Setting the potentiometer in zero value and measuring the Cathode to Anode voltage you should get something in this range. If you are getting 3.4V – 3.5V it is ok, but above 3.5V it is not good, so replace 47ohm resistor with a larger value (use calculator to find correct value) for this current limiter. This completes our modification. Power up the unit and set LED brightness at desired value.

Definitely try the minimal setting! The display will turn beautiful dark blue, and in late night hours you eyes will thank you. Plus it will live much longer. As a matter of fact i always have my TG-77 at this setting. It is still bright enough.

Semi manual backlight control?
Of course it is possible. If you don’t want to mess with a potentiometer but just want a fast switch for reduced backlight operation to extend the life of your backlight i.e. when you don’t work on the unit directly but use it remotely and thus not need the display. If that is the case then you can simply add a switch to the back. At the switch Position 1 you will put a 47 ohm resistor and at the switch Position 2 you will put a 1k ohm resistor. These are the values that I have found to give a good response. The rest of the modification is just the same and in the the above schematic just replace the potentiometer with a switch.

Newhaven display modification
Essentially you will do everything as described in here: Korg Wavestation A/D LCD Upgrade
Except that you replace the current limiting resistor (100 ohm) in that article with a wire that goes to the potentiometer with a 47 ohm connected onto. From potentiometer you go to the Red wire of the Newhaven display which goes to the Anode and you are set. The hole and the potentiometer go exactly as shown above.