# My Yamaha KX88 desk integration project



## tebling (Sep 4, 2021)

I'm about to embark on a bit of a project, and figured I'd document this here in case anyone else wanted to follow in my footsteps.

*Background*
I'm a pianist, and I've always wanted a great feeling 88 key controller at my fingertips. Anyone who's been around here for long knows that there's a real gap in the market for such a controller that "does it all". Every single one has trade offs, and most people don't have the resources to be able to try everything available. Search here for "88 key" and you'll quickly see what I mean.

Last week I finally got a fantastic desk that will accommodate not one, but TWO 88 key keyboards! It's a sit / stand desk with sturdy pull out drawers specifically designed to withstand this type of load (rated to 400 lbs). I also decided to try out an Arturia Keylab 88 Essential just to see what the low bar is for an 88 key controller today.

Here's a photo of that set up (desk is in standing mode):







Ergonomically, I love the setup! But I despise how the Keylab Essential feels under the fingers. I knew I was getting a "synth action" keybed but most of the synths I've played feel much livelier, whereas this just feels "dead" to me. I know plenty of people love these, so each to their own, blah blah blah. So the hunt continued...

I noticed in my research that many people called out the old Yamaha KX88 for being one of the best feeling keybeds they'd tried. I'm a bit old school myself, so I thought hmm I should look into this. Lo and behold someone was selling one nearby for a mere $120! I rushed over and paid cash on the spot for a near pristine KX88 from the original owner, who bought it in '86 and gave me all the manuals and the original receipt!

As others have pointed out, this thing is a BEAST and in total weighs 66 lbs! But oh man, under the fingers it's soooo good. Very heavy action to be sure, but the tactile feedback is wonderful.

Here she is, right after buying:






*Project Goals*:

So now I have this massive tank of a keyboard, but it's too big to sit on the pull out drawer - and likely a bit too heavy. So here's the plan of attack:

1. Crack open the KX88 and separate the keybed from the chassis.
2. Extend the cabling between the keybed and the electronics by about 1m.
3. Install the keybed-less chassis under the desk, at the back - out of sight, but within reach of all the cabling.
4. Install the keybed by itself on the desk drawer.
5. Profit...
6. Until I get sick of how ugly the naked keybed mechanism looks and want to build a proper wooden "pit" for it so it looks like a professional install.

*Step 1 - separate the keybed from the chassis* - *DONE!*

This was the easy part! Opening up the KX88 involves removing four little screws from the top panel, and then removing two screws from each side on the bottom of the chassis. The panel flips open on hinges.

Removing the keybed involves first dealing with the cables. The easy one is a 30 pin ribbon cable. Just pull it out from where it attaches to the electronics on the panel.

The second, and trickier one, is the aftertouch strip. There are two small wires that run from this strip into a harness with other wires and then to a connector on the panel. I decided to cut these wires near the keybed in order to splice in an extension. Here's where these wires attach to the aftertouch strip on the keybed (yes there's some dirt to clean up!):






With the cables removed, now it's a matter of removing the keybed itself from the chassis. This involves taking out three sets of three screws from the inside, on the back of the keybed. Then you have to also remove the remaining screws from the bottom of the chassis. Voila:






At this point, you'll notice that the keybed itself is still REALLY HEAVY! And this is where the secret sauce is revealed. Check it out - there are actual _lead weights_ attached to the underside of each key! They don't make 'em like they used to, because it's probably illegal now 






(continued in the next post)


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## tebling (Sep 4, 2021)

*Step 2 - extend the cables (in progress)*

This is where I'm at now. Splicing an extension to the aftertouch wires should be pretty straightforward. Extending the ribbon cable is a different matter.

The ribbon cable is a bit weird, and actually has three connectors: one 20 pin cable for the lower half of the keyboard, then a 30 pin cable for the upper half which is crimped in the "middle" of the cable, then finally another 30 pin at the far end which attaches to a header on the PCB.

Here are the two ends of the cable:






And here's the funky connector in the "middle" which goes from 20 pin to 30 pin.






At first I thought I could buy a 30 pin extension cable with male and female ends and quickly be done with it, but for the life of me I can't find such a thing.

So now I'm thinking that I should build a longer replacement cable using new parts. Wish me luck!


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## Markrs (Sep 4, 2021)

Will be excited to see how you get on with this as the keybed looks very nice being properly weighted.


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## Double Helix (Sep 4, 2021)

This is great! I am a die-hard advocate of the KX88, so I'll be wishing you success--$120 is a super deal, and local pick-up? What a bonus! Midi-mapping galore, too, which was unusual back in its heyday.
It appears that you know what you're doing, and cool that you are documenting the process.
Onward!


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## Paulogic (Sep 5, 2021)

Maybe you can use/assemble a 30 pin ribbon cable with 2 x female connector and
build a connector strip yourself using a stripboard and pins ?

Just an idea, trying to help.


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## tebling (Sep 5, 2021)

Paulogic said:


> Maybe you can use/assemble a 30 pin ribbon cable with 2 x female connector and
> build a connector strip yourself using a stripboard and pins ?
> 
> Just an idea, trying to help.


That's not a bad idea, and I appreciate the help! I could buy two 30 pin headers and put them on a PCB like you've shown, and just couple them together.

I think that's a reasonable Plan B, but I still think it will be easier making the cable - and I now have a IDC crimper on the way so I'm committed to that plan  Stay tuned!


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## tebling (Sep 9, 2021)

*Step 2 - extend the cables (update)*

Ok, so I made a new ribbon cable and it was way easier than I thought it would be! It's all about having the right parts and tools. Here's what I used to do that:

1. Ribbon cable, 1.3m long, 30 pin, with female sockets on each end (2x15, 2.54mm pitch). https://www.amazon.com/gp/product/B07JPLNW5B (Link).
2. IDC cable connector kit, with crimp tool (includes 20 pin, 2x10 female sockets). https://www.amazon.com/gp/product/B07WHFWMYQ (Link).
3. 30 pin female IDC connectors. https://www.amazon.com/gp/product/B07WP9NLDJ/ (Link).

Here's the connector kit and crimp tool, with the 30 pin connectors in the bag on the right side:





The steps to make the new cable were pretty straightforward:

1. Remove the 30 pin connector from one end of the new ribbon cable.
2. Use the crimp tool to attach a new 30 pin connector (part #3 above) about 14" from the end you took the connector from in the previous step.
3. Now along this 14" length of cable you need to separate 20 pins on one side from the other 10. If you used rainbow colored cable this is easy because the colors repeat every 10 pins.
4. Cut off the 10 pins at the 30 pin connector you added in step 2. You don't need these.
5. Now use the crimp tool again to attach a new 20 pin connector at the end of the cable, and trim the excess cable.

That's it! You just need to make sure that when adding the new connectors that you orient them properly, using the original cable as a guide.

Original cable in the background, new longer cable in the foreground:





New cable plugged into the KX88 keybed:





And attached to the electronics in the chassis:





Of course, the big question is - did it work? Much to my relief, YES it worked!

I grabbed an old audio interface and my laptop and did the experiment on the living room floor (much easier than lugging this thing into my studio just for testing purposes).

Next steps: extending the aftertouch strip cable and mounting the chassis to the desk!


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## tebling (Sep 12, 2021)

*Update - project finished! (for now)*

Summary: *the chassis and keybed are now installed in the desk and everything is working! * Except for aftertouch, which I may look into fixing but isn't a big loss for now.

So as it turned out, mounting the chassis to the desk was a bigger pain than I thought it would be, because of the particular hardware I bought to support it. The section of wood at the back of the desk that I was mounting to came up a bit short for being able to attach the supports - so I had to figure out a way to extend it lower. Here's what I came up with, viewed from behind the desk (excuse the rat's nest of cables):






What you're seeing here is that I used a miter saw to cut out a half lap from a couple of cedar 2x4 pieces. These are held to the desk by 2" long carriage bolts, and provided the necessary extension to install these "https://www.amazon.com/gp/product/B01KMBW8PG (bicycle storage hooks)" low enough to accommodate the chassis and provide a flush surface:






From there, it was a bit of a pain getting the chassis installed. Despite my measurements, it turned out to be just a couple millimeters too wide, so I needed to remove one of the end caps. Once done, it fit perfectly! I had to install it upside down as well, to accommodate the power cord which attaches to the back.

Here it is - the view from below the desk, with the keybed hooked up:






Unless you're crawling around on all fours, you'll never notice it:






For some reason aftertouch doesn't work, even though I've verified that the KX88's internal controller assignment is set up correctly. I must have bungled the wiring somewhere. Like I said, it's not a big deal. As cool as aftertouch is, I rarely use it. Here's a close up of how I extended the aftertouch strip wiring using a Wago style connector:






So was it all worth it? *YES!* I lost a good hour last night just jamming with my favorite piano library and loving the feel of these keys. Mission accomplished, and I couldn't be happier with the end result! And as with any other project like this, I learned a ton in the process and that of course is a big part of the payoff.

But as with any work of art, it's never really done. I'm already dreaming about building a simple wood enclosure for the keybed so that a) it's not so ugly sitting there naked, and b) it rises closer to the desk surface. But that's going to be a ways off. For now, the music calls!


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## chimuelo (Sep 12, 2021)

Fantastic idea.
Twas my first controller w/ the QX-1/TX816.
Yamaha was way ahead of their time w/ PAT on the CS80 and weighted KX series action.


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## mybadmemory (Sep 12, 2021)

How come you installed the entire chassis underneath the desk instead of just the internal electronics?


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## tebling (Sep 12, 2021)

mybadmemory said:


> How come you installed the entire chassis underneath the desk instead of just the internal electronics?


Yeah, I thought about that - but separating the electronics from the chassis would be a whole different level of modding. I wanted to retain the ability to use the panel buttons, and I also wanted to keep the option of returning the whole thing back to stock without too much drama. Saving weight from the chassis wasn't nearly as much of a priority as minimizing weight on the slide out drawer (keybed).


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## sylent01 (Sep 12, 2021)

I loved my kx when I toured. Alas those lead weights eventually fatigued the plastic keys causing them to crack/break and I lost about 2 1/2 octaves worth and had to replace them. You might want to pick up another for scrap since you can’t find after market keys any more. YMMV however.


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