Making a midi keyboard shorter

[the19thbear]

Hi. Basically I want to make a midi keyboard i have, shorter by one octave.
I have the row of contacts here, with all the diodes etc. How should i go about making it shorter? In a perfect would, i would be able just to cut the circuit board shorter, end of story. But im guessing i'll end up with some keys not working..

Thanks

[seraph]

what about selling the one you have and buy a shorter one?

[JovianPyx]

I agree with seraph, it won't be a simple job to just slice the keyboard.

The designers of those boards do not take into consideration such modifications, so circuitry placement would be fairly abitrary from that standpoint.

If you don't have the schematic and all of the required skills to restore all necessary circuit paths, then this would be a very risky adventure likely to end in failure.

[Cynosure]

This is the first time I ever heard of someone wanting a shorter keyboard.

Like JovianPyx said - if you cut a required trace on the PCB then you could screw it up.

However, if you carefully follow the traces on the end that you are removing and see that the only place that they are going is to the key switches, then it might be ok. Most scanning circuits will be checking for a closed circuit from the key switch, so removing it would just make it permanently open.

A service manual would help you identify the traces and if it is possible to only remove the desired keys. What is the make and model of the keyboard?

I am curious - why do you want less keys?

[blue hell]

Hmm .. well .. there was this person before wanting to cut a Nord Lead in two .. eventually that led to the .. what was it !v chat command? ... (recently i cut my X in half .. oh my ex eh :¬| ).

Apart from that - if you'd want to shorten it you would want to know where all the PCB traces go and what hey are good for; as you already said some other keys may stop working. Probably the keys are put into a scan matrix - so there will be row and column lines, cutting one wrong track may cut an entire set of keys further on on the keyboard, or key on would still work but velocity would not work anymore, stuff like that.

Anyway, when you decide to go on anyway - good luck, and keep us posted :¬)

[bubzy]

buy one of these

http://www.ebay.co.uk/itm/like/350730811060?lpid=83&device=c&adtype=pla&crdt=0&ff3=1&ff11=ICEP3.0.0&ff12=67&ff13=80&ff14=83&ff19=0

cheapest midi keyboard around.
save all that cutting in half business.

[PHOBoS]

[Broadwave]

If the keyboard has a standard diode matrix, then it's fairly easy to cut down - as long as the matrix PCB is logically laid out (most of them are), and usually only from the top octaves down.

Each key has a pair of associated diodes (note and velocity), so you'll need to find the pair for the last note you need. You can then cut the PCB from that point as well as the keybed.

It can be done, I've recently cut down two CME M-Keys from 49 (4 octaves) to 37 (3 octaves).

[richardc64]

[bubzy]

recently I cut my grass in half.

https://twitter.com/Bubzyg/status/366562794323181569/photo/1

[Broadwave]

[the19thbear]

well whatayanohw - Its not needed anymore - but thanks for all the suggestions and smart remarks - I'll end up using the full range, but put pitchbend/mod wheel somehwere else in my design so i actually have room for the whole keyboard..
thanks again!

[Manuel Marino]

why cutting a keyboard? honestly, what's the reason? use it in clubs while playing dance music?

bring it in your favourite sack while doing a travel around the world?

or simply, removing the octave that doesn't work anymore after years of playing?

[the19thbear]

Making it fit here:
http://electro-music.com/forum/topic-59305.html
-The midi keyboard is a Yamaha KX49 with a built in arp that I want to use with this synth.

[Manuel Marino]

ah! ok, now it's more reasonable... well, just a "bit" more