Bought a DX21 , What r these pieces?

What could this be?

The lowest key doesn’t work and I’m wondering if the pieces in the picture might be the reason.

Greetings from Eckernfoerde.


Dear Syntaur team,
What would I have to do to get the lowest white key/left most key to work again?
Is it even worth the hassle?

Paid 99Dollars for this beauty.

Not too sure what those pieces are, but I think they’re probably not the cause of your key problem. There’s a few different faults that can cause keys to stop working. A good place to start is with cleaning the key contact board at the contacts for that key. You can use 70% isopropyl alcohol and a cotton swab to clean the contacts. We have a more in-depth blog post about this topic here: Keys not responding correctly? Check the contact strips. – Synth Wizards.

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Thank you for the advice!
Will read up and check out the contact strip.

Hello again Syntaur Team,

So I disassembled the DX21, and cleaned the piano key contacts
I also noticed that one of the green buttons doesn’t work.

So the only faults are:

  • one key doesn’t work (but I think that problem is now resolved)
  • One green button doesn’t work. ( Pitch modulation amplitude)

Concerning the green button:
The button clicks and I can’t see any oxidation or damage anywhere on the PCB.

I vacuumed all the dust out of the synth.

Should I spray the buttons with Deoxit F5 ?

…Also, when reinstalling the contact strip, it now seems to be a little too long. Is that normal?
I can’t remember it being that way when I took it apart.

Thank You

I put it back together, the green button works all work now​:blush::+1:
I sprayed it with Deoxit.

But, now only 30% of the keys work, lol😁.
Can Deoxit cause the rubber strip to expand?
Because it didn’t fit between the foam ends.
I kinda let it soak in Deoxit F5.

Or did I install it wrong?

I have a DX27 that had a few dead keys. Same keybed.

I don’t know what effect Deoxit F5 will have on the contact strip, but it does sound like it was soaked up like a sponge. The strip is actually segmented so that each group of keys has it’s own section. If it’s expanded, those sections might not be making contact in the right places.

I don’t use any solvent when I clean rubber contacts: I use nothing more than a damp cloth. You’re only trying to clean off surface dirt. And then a little bit of IPA on the circuit board contacts.

I would take another look at that strip. Maybe you can clean it or dry it out? I’ve heard that you can repaint the conductive section of it, but it might be easier to find a new one.

The buttons are typical. They have something like a 500k press lifespan, but they’re not sealed well and begin failing. (Or else spraying Deoxit wouldn’t help it.) When one fails, expect to have issues with the others. I just replaced all of mine to future-proof it.

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Well, I guess now I need a new contact strip😵‍💫.

Thank you for the reply.

I am going to attempt to cut it to length. I got nothing to lose now, lol.
Cleaned everything with cleaning alcohol again.

After I cut the strip to, I I think it was, 5 equal lengths and one real short one, I almost got all the keys working again.
I also gave the contacts another good wipe with alcohol.
The left most key works as well.

Yet, I think the strip is at the end of its life cycle. May have to order a strip from Syntaur.
Too bad we don’t have a Syntaur in Europe.

There are companies in Europe that are similar to Syntaur. I have even had to resort to buying parts from them when I can’t find them in the US. As crazy as it sounds, I have even picked up some of my parts through eBay.

You have to consider that the DX27 is no longer supported by Yamaha and most of these parts are no longer being made. Some of the parts you see available from Syntaur (and others) are actually reclaimed from keyboards that are deemed non-repairable for various reasons, (Syntaur labels these as used,) so they might not always be available. And some of the parts are actually custom made for Syntaur. It isn’t unusual to rebuild a volume control/slider because there just isn’t any alternative. And sometimes you have to do a little bit of redesigning in order to make something else work.

Here’s an article about repairing the contact strip. It’s based on the DX100, but the same principles apply. I consider it an extreme repair, so do NOT jump into it unless you have exhausted all other methods. There are small vials of conductive paint that might prove more workable.

It sounds like you may have lucked out if you’ve got the keys working again. Getting a replacement may take a lot of searching. The Yamaha part number is CB828630, and it is used in the DX9, DX21, and DX27. If you can find one sold for parts-only, you should consider it - a good supply of spare parts.

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Thank you for ur reply…

Yes, I have already read the article from tubbutec and thought about ordering the 33 spray.

But, since this morning, ALL keys now work.

Summary of all the stupid and smart things I did, lol.
Firstly the stupid:

  • I soaked the entire contact strip in Deoxit F5.
  • I also sprayed the contacts on the PCB with F5.
  • Being soaked, the rubber strip expanded. So, I had to chop it into multiple sections for it to fit onto the PCB.
    (Practically destroyed an irreplaceable part)

Now the smart things I did:

  • I cut the rubber strip right at the sections where the black tube thing is interrupted and trimmed each piece to exactly fit the PCB layout.
  • I wiped off the Deoxid with alcohol.
  • I turned up the heater and placed the reassemble DX21 right next to it, and left it over night.
    My thought being, that there was still some alcohol and Deoxid residue b on the strip and board. The heat/ warmth would cause it to evaporate.

Now magically all keys work.

Although, at first there were still 3 to 5 dead keys. After repeatedly tapping them and playing some arpeggios the keys slowly started to produce crackles and came to life.
I was so happy.

Going forward, I will probably use a midi keyboard to keep the wear and tear at a minimum.

*Update: just now found a guy who has a rubber strip! lol

Blockquote *Update: just now found a guy who has a rubber strip! lol

An omen. That’s great! I would recommend picking it up. If that strip causes any more trouble, you’d have the part you need on hand.

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