Introduction: Dramatic Yamaha DS-55 Keyboard Synth to Module Conversion

About: I'm an expert amateur. I love to practice, design, make, fix and modify all kind of stuff. I love music, play guitar and synthesizers. To cook it's my favorite way to meditate

This is the story of a synth that was bought from a thrift store to take a new and better life. But destiny make him pass through several bizarre situations, mistakes and all kind of crazy stuff. After several surgical interventions now this amazing and unfairly underrated FM synthesizer has a complete new life, retired with his player and surgeon in a comfortable house in Madrid (Spain), with his family of Yamaha synths and home keyboards and all a new crew of Casiotones, with whom he plays absurd music almost every day.



  • A synthesizer with a non workig keyboard, in this case a YAMAHA DS-55
  • A wine bottle box made of wood
  • A bunch of screws
  • Electric tape
  • Solder tin
  • Hot glue bars


  • Electric jigsaw
  • Dremel with 3mm drill
  • Solder
  • Hot glue gun
  • Generic tools as a hammer, screwdriver, etc.


  • Protection glasses when cutting plastic
  • A mask and ventilation to avoid breathing plastic gases when cutting or when soldering
  • Be careful with electric parts. In some moment you will need to probe the synth out of its case. PCBs, cables and metal parts touching each other can carry your synth to complex damages.


  • Know that everything can go wrong
  • Some soldering skills
  • This is an iterative trial and error process, be patient and careful
  • Respect every screw and every little part, try to respect the work of the engineers that designed your synth ( if possible)
  • Keep calm and carry a towel

Step 1: Go and Buy a Yamaha DS-55

You can get it cheaper if it powers on but seems to not play anything or only play weird sounds. Don’t worry, it will be easy to fix, you only will have to change memory battery and proceed with a factory reset.

To factory reset a Yamaha DS-55 simply turn on and then push TUNE + STORE + START/STOP + SELECT + 0, in that order and keeping pressed each. Then press YES, then 1 + 7 Then YES and again YES.

This will solve lot of strange problems like only alternative keys playing, and lot’s of things that you wouldn’t imagine that can be solved with a ‘simple’ factory reset.

Step 2: Walk Happy to Your Home and Don’t Worry About Sidewalk Cyclists

Go happy with your new synth just like normal, it’s very improbable, but may be that a crazy angry cyclist going like a bullet by the sidewalk hit you and make you throw the synth to the floor. After that, also improbable, that mad #&!? cyclist don’t even stops to tell you a little sorry.

Don’t forget to try to do this at night and pass a lot of time trying to figure out which parts of plastic, screws and other stuff are from the synth or was simple micro-waste that was there.

Step 3: ​Check the Damage

Arrive to your home and start to disassemble everything and start to evaluate the real damage. You will check that, of course, you didn’t searched enough in the street for all the missing parts.

Step 4: ​Repair All the Keys

You will fix each key with some experimenting, using epoxy and some other things like sewing pins to complete the work. Don’t forget to change the battery. It’s a CR2032 battery, and with some thermal tube and 2 pieces of cables you will make one so much cheaper than any other.

Step 5: Ignore Some Spacer to Produce Another Disaster

Ignore that strange cylindrical spacers under the keyboard PCB are important, don’t check it, forgetting only one it’s enough. When you start to put screws you will listen a very audible crack. Yes, you have broken the PCB and 4 tracks separated by 0.2mm.

Step 6: Try to Fix Broken PCB Little Tracks

This tiny tracks were impossible to fix by me. Liquid silver didn’t worked. And solder something was getting things worse. Furthermore, this tracks are under the silicon pads, so anything that would leave a lump would have felt bad when played or even leaving it not playable. So, go to the next step.

Step 7: Leave the Synth in a Corner of Your Workshop Collecting Dust

Forget your synth, disassembled, ignored, unfairly ostracized. And look from time to time Ebay and similar places waiting for a new keyboard PCB without success. 4 or 5 years for this step it's enough.

Step 8: Wait for a Global Pandemic and a Lock Down. Wild Ideas Will Arrive

In the middle of a pandemic it’s a perfect moment to have time and wait for new and radical ideas coming to you. And you remember that amazing mod of a Microkorg that with a broken keyboard was modded to became a tiny module to be played with an external MIDI controller. ( Oh blessed MIDI protocol and DIN connectors ).

Also you have luck and there is a wooden wine bottle box from some Christmas that you collected that has a close to perfect fit with the main PCB of the synth ( wooden pine wine boxes are awesome, you can ask in good restaurants for them also ).

Step 9: Real Instructable Starts: What to Preserve

At his moment you are planing how to put all the important parts in the fewer space possible. This not bad vector images I’ve made would helped me a lot to have a better idea. But the real situation is that I simply cutted out the main parts. Those are:

  1. The buttons and screen interface that are connected by steel to the mainboard.
  2. The expression wheels, earphones and breath control jacks and volume control module
  3. The piece of plastic with the name of the synth and main function described

It was important to preserve the piece with the name of the synth, not only for structural purposes, but for giving the final undecided result its original character. Preserving even the metal sticker with the name of the shop that sold it for first time.

Step 10: Cut Some Plastic

As I was possessed by the inertia of the idea and I didn’t haf the right tools, that were in my parent’s house (remember this is April 2020 and Spain it’s under strict lockdown and my parent’s house it’s outside the city), I used a jigsaw and no marks or anything than the intention of cutting it out. May be that aa circular saw with a guide would made a better job, or some kind of guide with my 20€ jigsaw, but I only started to cut.

After that all the parts could fit in the wood wine box.

Step 11: Be Careful When Using the Synth Without a Case

At his moment you can even play the synth as it is. The buttons/screen part can be used with it’s original assembly and the expression/volume module can lay around.

But this will lead you to bend the big transistor sink that is one side, and eventually you will do this so many times that you will have another drama looking for what happened. It happened to me and I broke the contact around one middle leg of one of the transistors (photos above), and I had to solder a wire bridge to fix it ( yes, this is a big sequence of messes ).

Step 12: Replace Old Degraded Contact Swithches

This synth has rubber encapsulated contact switches that can get corroded, stuck, or degraded in any way over time. So measure carefully the dimensions of the switches to go to your local electronics store and end buying switches with dimensions totally different, because they don’t have more sizes and you are a little hurry. They also don’t have the quantity that you need, so pray for having enough working old switches.

This new switches worked well have a good fit, touch and feel and there are enough good working old switches also, so... Nice done!.

Step 13: Start Designing the New Case

One of the possibilities was simply ignore the expression module, and put the volume control and jacks somewhere over the case, but I decided to preserve them as there are very cheap only keyboard MIDI controllers from 90’s that would be perfect for it (Anyway I have a very nice USB-DIN MIDI controller that you can see in the video).

So after some trial and error I decided the final position of each piece. This process was not straight forward as I initially wanted to preserve the connection between buttons and PCB module, but the inclination of the button interface made it impossible to let home between the expression wheels and the PCB ( Here I was very conscious about this danger, look the overexposed photo above to see this ).

Step 14: Cut More Plastic and Glue It

After final design is decided, it’s time to put all the original plastic parts together. You will need to cut the less important part to adapt to the most importants. In this case (the case of the case) I decided to cut the brand-model piece to adapt to the buttons and expression module.

Also I cut some plastic structures under the buttons module to make it fit with the width of the front planks from the box.

Step 15: Mod the Wood Box to the New Dimensions

With a clearer idea of the final result you can start modifying the wood box. Simply place the mainboard and the glued plastic top cover and take some measures and mark with a pencil. Remember don’t make like me, measure twice and cut once.

Next you have to disassemble the wood box. Those cheap wine boxes are nailed with pneumatic hammer nails and staples, so it’s a little tricky to remove each plank without damaging it. If damaged, simply glue, clamp and wait.

You can see the result in the photos above.

Step 16: Prepare Main PCB Fixing to the Case I

As while I was making the case I had no idea about all the minor solutions, I decided to reinforce the lower metal cover of the main case with some pieces of wood. Finally it was not necessary, but I show you this because this was the first time I glued wood and metal successfully with hot glue.

The main problem when you try to use hot glue with metals it’s that metal temperature and capacity to dissipate heat tends to cool the glue too quick. So I decided to place the metal in front of an electric stove for about 40 seconds ( be careful with this, the thin metal can accumulate heat very quick and can burn you or something around this, as also the heat and hot air can reflect to strange directions).

Once the metal it’s heated, simply put the glue over the metal and then the wood. This will produce a very nice gluing.

Also I had to cut some metal from the top cover of the main PCB, as the screen cables from the screen didn't reached the thesired position.

Step 17: Prepare Main PCB Fixing to the Case II

Now the problem is how to screw all the main PCB module to the box base. So my choice was to make a new part to cover the uncovered part of the PCB. With only a piece of wood to screw would be enough, but at this point I had no idea of the height of the final result and I was worried about some component touching the main PCB. Finally I my decision was great, as i needed this cover to place a support for the top plastic cover.

For this I used some scrap wood that I had laying around. The fit was not perfect, but good enough. With this I could mark the original screw holes from the PCB module to mark them over the base wood plank. Then I drilled these holes in the wood, and then marking again from the bottom to the new PCB wood cover, with the PCB positioned of course.

Also I made a gap in this wood piece to let the expression module cables pass through.

So with this, the final fixing to the base would be three screws passing from the bottom base wood, passing through the PCB modules screw holes and then reaching the new wood cover.

Step 18: Add Supports to the Plastic Cover

With the main PCB placed the next problem it’s to fix the top cover to the wood case. Fortunately the Button module, that now it’s part of the whole top cover, it’s supported by its shape in the back plank. So now I marked with a pencil some critical places to support the other edges from the top cover.

With some scrap pieces of wood I simply glued it to the sides and front planks. Then I used a dremel to drill some holes to place some screws on it.

Step 19: More Screws and Supports for the Top Case

The new case it’s almost done. I decided to make 4 holes to fix the back part of the top plastic cover to the wood plank, tanking the risk of making then directly with the button PCB mounted on it ( I fuzzily measured and it worked ).

Also I added a support made out of scrap wood from the wood to give some reinforcement to the piece of plastic with the brand and model name. No screws added.

Step 20: Final Touches

To cover the shames of this design I used electric duct tape to coverthe ugly glued seams. The bottom piece of tape was removed almost immediately as it was worse than not having it.

To end this project I put some felt pads for the two positions that the module can be placed. But my favourite it's vertical one. It's like a digital modular interface saying 'Please play with my buttons and look to my awesome screen'.

Step 21: Result and Conclusions

You can see the result of this war of me against adversity and the poor synthesizer against my sloppy actions. It works. Its punk looking is good enough for me.

With all this steps done and exposed I could make a better case, so much good looking, but for me it’s ok. It reminds me that I need to be more patient. But this was not an easy task. There is too much trial and error, and some errors have can’t be reversed.

In this case I decided making an instructable just after cutting the main pieces from original plastic case. Appart from this inconvenience, compensated by the comic and some vector illustrations, to improvise something like this and documenting it at the same time it’s a hard task. You need to keep your mind looking in two directions; the project and the instructable. I feel that it’s good enough to publish but I have no idea if it has something clear for anyone else. Please feel free to comment about this.

Other thing it’s that I used my phone camera, and I see a clear lack of quality in my photos. I have some other instrucable ready projects made with my phone camera, but others ready to make from zero will be photographed with mi DSLR.

The only modification that I’m planning to implement it’s to add a button to emulate one lower key from the original keyboard as it is needed to trigger the arpeggiator and other sequencer functions. I preserved the original PCB cable, so I have to investigate the keyboard matrix to achieve this. Sadly when I took the keyboard PCB and all the non usable parts to my local waste management plant I didn’t realize about this.

I hope this instructable can be useful for somebody that have something similar in mind, not only for making a Yamaha DS-55 module conversion, but for any synth or device susceptible of being transformed.

Also I hope you enjoyed it so much as I did making the project and the instructable.

I’m open to all kind of comments. Thank you so much!

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