DX-7 Keys?

esoteric · Post by **esoteric** » Wed Nov 21, 2007 4:42 pm

Long time lurker, first time poster. Be gentle.

I just picked up an old Yamaha DX-7. It's in good shape except that one of the black keys doesn't spring back up. If I lift it up and let it go, it drops and triggers a note. It also sounds like it's responding to aftertouch, so I don't think there's anything really wrong with the wiring for that key.

But I'm totally clueless about the mechanics of key action here. Is this something that I could repair fairly easily, possibly with the purchase of a replacement key?

Thanks!

eskimo · Post by **eskimo** » Wed Nov 21, 2007 6:04 pm

I have never gotten inside the key mechanism in a synth before either, but I would imagine it's a system of small spring and plastic tabs that would keep the key in an upright position.
You probably have a broken tab, or the spring fell out of the locks.
If you're a take-it-apart type guy, I'd give it a look. Otherwise I'd just take it to a local organ-piano-keyboard fix it dude.
Broken keys in all forms are easy fixes .. usually..

zmd · Post by **zmd** » Wed Nov 21, 2007 6:09 pm

on my old dx21, it was just an upright spring at the back end of the key. all i had to do was lift the key out from the front... a little wiggle action and it came right out. the spring locked into the key, and i wiggled it back in, and voila!

eskimo · Post by **eskimo** » Wed Nov 21, 2007 6:17 pm

This is an interesting DIY page for Key issues.
http://indra.com/~cliffcan/01keys.htm
It's for a Korg 01/w, but they mention a bit that the DX7 is the same key module. It's worth a look.

Uncle Screwtape · Post by **Uncle Screwtape** » Wed Nov 21, 2007 8:49 pm

I've seen two different cases like this.

One was just a misalignment, the other was broken. In both instances, the pivot point was at the very back of the key, and the spring was in front of it. The key slipped forward slightly and came away from the retaining mechanism. The spring tension then pushed up on the rear portion and pivoted against the top panel. This effectively made the front portion push downward.

If you're lucky, this can be fixed without opening the unit. You can grab the front of the key and pull up on it, while pushing downward on the rear. Then try to slide it backward - deeper into the chassis. It takes a little bit of force, but don't push too hard, or you may break the "clip" on the key. If the "clip" at the rear of the key is already broken, it may stay in the proper position, and pop back out when played. If it's just misaligned, it may snap back into place and Ta-daa! You fixed it.

Good Luck!

DX · Post by DX » Sat Nov 24, 2007 1:17 am

I know quite well the DX7 mechanism.

There is a "spring" (really a metal piece that do the job). Surely, that metal piece is lost under the key.

Here you have some pics:

(altought it is understood, I place here a warning that I placed in other repair process)
WARNING: This is technical information destined to showing my own fixing process, and for information purposes only . If you are going to do this job, you are doing it under your responsibility. You must have electronic knowledgments to do electronic handling. I don't respond about any damage on your system, including injury yourself. Be sure your DX is UNPLUGGED. Note that some capacitors at the power supply area can have charge inside. They can hurt you even with the plug off. Thanks

It is needed to open the top cover (there are 4 screws in the front plus one rear close to the Power switch). Remove them and Then lift the front panel.

Now you have to remove this (just pulling up):

For removing a key, just push it towards ahead WITHOUT PRESSING IT AT THE SAME TIME. IF THE KEY IS LOWER THAN OTHERS; LIFT IT MANUALLY BEFORE PUSHING TOWARD AHEAD. Underneath the keys there are the metallic key contacts. If you try to remove a key that is even slighty pressed, you can bend and damage that contact.
Pic of the contacts:

If you notice the key can't be removed, look for the closest keys and remove them first. Afair, the black keys need it.

Put the metal spring right in its place in the key (see pics above). Now it is coming the main step; remounting the key in the assembly. It requires some practise:

With the spring right placed in the key, you have to place the key and slide it towards ahead carefully (AT THE SAME LEVEL THAN THE OTHERS. DON'T PUSH IT). Look for the spring reaching a hole where it fits in the assembly. Probably the first time, the spring is falling of the key before reaching his place, so you will need to repeat again the process. Think after you are in success one time, then the following are done.

BTW; check that a piece of metal under the key (like a tongue, see the last pic), is in its place and it is not bent or damaged.

Hope it helps...

DX

DX · Post by DX » Sat Nov 24, 2007 1:28 am

PS:
It would be great that these kind of topics could be sticked in somewhere. I posted a similar thread months (and lots of) ago with that pics for a DX7 keyboard disassembly and remounting, and it must be erased for server space issues I guess.

crow · Post by **crow** » Sat Nov 24, 2007 1:30 am

DX wrote:PS:
It would be great that these kind of topics could be sticked in somewhere. I posted a similar thread months (and lots of) ago with that pics for a DX7 keyboard disassembly and remounting, and it must be erased for server space issues I guess.

No. Only because people think its better to ask if Staus Quo ever used a Moog Modular on " Caroline. ".
Pushes most else out.
A star stucky scheme may help this. it aint standard or easy on PHPBB.

DX · Post by DX » Sat Nov 24, 2007 1:47 am

Hah sure.

I've been thinking about a "Little handyman place" with some easy jobs like a broken/lost key, or even major improvements (for more qualified and electronics knowledgers) like the Akai S3000 XL internal hd mounting process I posted in Samplers months ago.

It is a pity to write the same every year for givin' help to some folks.

crow · Post by **crow** » Sat Nov 24, 2007 1:58 am

DX wrote:Hah sure.

I've been thinking about a "Little handyman place" with some easy jobs like a broken/lost key, or even major improvements (for more qualified and electronics knowledgers) like the Akai S3000 XL internal hd mounting process I posted in Samplers months ago.

It is a pity to write the same every year for givin' help to some folks.

Save them to your own website.
just post a link then.
very easy and not costly at all.
saves the re-typing.

DX · Post by DX » Sat Nov 24, 2007 1:18 pm

That's a cool tip, crow.

But I 'm afraid it is the same problem. If the post containing the link is deleted by age, It will be lost too.

Anyway I will save my post text in php format into a text doc, for re-posting if neccesary with a simple copy/paste.