Modifying CTK Keys For Feel & Quietness

[mlochala]

Hello everyone!

 

I have a CTK-6250 that I bought several years ago for the purpose of making it easier for my daughter and I to have improvised practice sessions at home without all the trouble of dragging out my more professional gear each time.  I actually became more impressed with this little "cheap" keyboard than I expected and have used it here and there when playing it away from home.

 

However, there is one little gripe I have about the keyboard, which I am hoping can be rectified.  There is still, to some degree, a clacking sound which occurs when playing the keyboard that I find annoying.  Also, although the feel isn't terrible, I would love for the keyboard action to be somewhat improved.

 

My question is, has anyone ever done any modifications to this or any other similar keyboard to improve these issues with these boards?  Yes, I know the simple solution is to purchase a better keyboard, but it just seems that it could be possible somehow to eliminate the clacking sound and maybe even improve the overall motion and feel of the keyboard itself.

 

Has anyone done this?

[Chandler Holloway]

@Jokeyman123 would be the one to ask. He's done some modifications to the keybed of his XW-P1, which uses the exact same keymech as the CTKs and WKs of the 6250's era. If you're lucky, he might even share some pictures of his handiwork... I haven't been able to find them looking through his post history (it's very long).

[Jokeyman123]

Hello-just checking in. I still play the XW and had the CTK6200 the slightly older model of 6250, a very nice sounding  portable Casio. I had disassembled that too and yes the keys are very similar but i don't recall if the various key assemblies are identical-going by memory, I think they are and are in sections.

 

I did perform 2 modifications one of which is not really a modification, and might be causing the clacking.

 

One source will be the upper back part of the key-this could be hitting the top frame when the key returns. and if this is so, the screws that hold down the various sections of the keys can work loose over time-mine were loose and I added a little "loctite" which is a thread "sealer" that prevents screws from creeping out-but does not glue these in if you need to remove the screws later on.

 

The other source-at least with mine was due to the layer of cushioning felt which is glued beneath the key assembly in one long strip. This is mounted directly to the bottom plastic case inside, and if this is worn, the plastic key tabs that rest on this strip will sound as though there is a plastic to plastic contact-which there may be if the felt strip is worn sufficiently. I needed to find a suitable "piano felt' material and-carefully-glued this new strip directly on top of the old one. It was not necessary to remove and completely replace the original felt strip as it was worn thin enough as to not interfere with gluing the new one. The procedure is a little tricky-you might want to use thin double-sided carpet tape instead of glue which will work also. Not sure which Casio it was-but I had to make a long metal rod from an old coat-hanger which acted as my "needle"-I attached one end of the strip to the "needle" with some sticky tape and pushed that through the entire keybed underneath-until it reached the other end-then I pulled it through in one shot to get the felt strip in place-then tamped it down. The trick is to not put too thick a strip of piano felt over the old one-as this will affect the key's travel-will shorten it a bit-and could interfere with the touch response-you might need to experiment a bit to see how this works. I need to hit the XW keys a bit harder-but i designed it that way as I am accustomed to piano weighted keys-and the extra felt under my hands was what I needed. I unfortunately do not have any disassembly pictures of the XW-I thought i had posted some years back-I will check to see if I saved some pics on my computers. taking the CTK/XW apart is not too difficult if you are handy. You may only need to lift off the top to check to see if the keyboard screws are loose and caousing the clacking. these ae right under the top front assembly, the control panel

[mlochala]

Thank you so much for your replies!  I appreciate it very much!  I might get a chance to work on this soon, after I get my Roland U-20 and Yamaha DGX-620 back together, of course.

[Jokeyman123]

Couple of other tech tips-for any keyboard or other electronic disassembly-get some "poster putty"-used for sticking paper onto walls etc.-I keep a bunch of this around to stick screws onto screwdrivers for hard to place or retrieve screws and other parts. Works where magnetic retrieval tools won't. I also use a jeweler's magnifying headset-my eyes are excellent, but these show up solder cracks or other defects you might not notice. And good lighting very important for the same reason.

[pianokeyjoe]

To add to Jokeyman123's suggestions for tricks and upgrades, I plan to glue small metal nuts to the inside of the keys to give just enough subtle weightiness to the keys of said newer Casios, to give a weighted feel. The all plastic construction of the keybeds and the key strip keys are flexible and bouncy enough that if you put too much weight it will be too bouncy and feel not right. I have to experiment with placement as the pivot points are not as stiff as with OTHER brands of keyboards, so this trick may hurt rather than help. Casio keys have ALWAYS been softer and easier to the touch than say YAMAHA and ROLAND keys. However, mileage may vary as the weighted feel in old Casio synths incorporated stiffer SPRINGS in the back. A lesson I learned one day changing an HT6000's non weighted keys with VZ1 synth weighted keys only to find out I had to remove all the keys again and use the VZ1 springs which were a different color btw, than the HT/CPS springs. That said, another thing to do along the lines of what Jokeyman123 said about the key felt, is find a FATAR or YAMAHA After touch felt strip and replace the felt you have default in the CTK6200(I have the same board, lofty plans ahead!!), and install the aftertoch strip and solder the strip in parallel with a modulation control of some sort to give you velocity AND aftertouch. The old CT6000 had aftertouch as did of course, the CZ1/FZ1 and VZ1 keyboards. The CT6000 used my same principal method and only affected vibrato? As such, even a simple connection to a pedal input can yield interesting results.. I will of course record and report my tinkerings as soon as my studio is built and I am back playing and tinkering again!!

[CYBERYOGI =CO=Windler]

In rumbly toy-grade keyboards I also often used adhesive window insulation foam rubber strips in various spots. Use the slightly more expensive silicone-based version, because cheap (PU based) foam rubber tends to crumble apart 1.) after a decade by ozone and 2.) by battery leak vapour (and possibly also less acrid things like oil smell) which makes a big mess.