key malfunction?

[mreitz]

hi all -

 

I have a wk-7500 that has served me well in all the time I have owned it and I relly think it is a good machine.  That saidl, just today while playing I found that I wasn't getting full key(s) response when chording with my left hand. Specifically, when key B3 is depressed I get no tones (noise) from keys C3 through F#3.   Also, and this is a bit hard to explain, if B3 is depressed ( it sounds )  and held down the aforementioned keeys do not sound - singly or in combination -  but if they are held down and the  B3 key is then released they ` do sound, although apparently the touch respnse is not effected since no matter what pressure is applied to the key(s) the volume of the note(s) is constant.  nAll other keys seem to be working normally.  Any thoughts would be appreciated.

[Jokeyman123]

I've repaired and modded several Casios-this is an odd one. My best guess is that the B3 key pressure may be causing some physical distortion in the circuitboard used for the adjacent keys-there may be a tiny crack in one of the circuit traces that opens and contacts intermittently, although weird that it happens with only one key and affects only a specific key range but it's possible. I recently repaired an intermittent note in another keyboard by noticing a slightly loose screw in the circuitboard under the bad key, tightened it up, problem solved. Could also be a simple operating system glitch that might go away with a reset, if there is one on the WK although that's a long shot. If you are not a tech or reasonably experienced troubleshootert, sounds like Casio factory repair is the place to go. Any disassembly by you will void your warranty, and I've already voided several of mine!

[monchito]

I have done it on higher end keyboards but have found that taking out the contact strip and reseating took care of those non working keys,, maybe you might want to try that..i have seen even small hairs even dirt get caught inside those key contacts over time but be careful not to scratch those contacts as they are covered with a special carbon material you should not use any type of cleaners. ,

[Jokeyman123]

I agree Monchito-I've made the mistake of using contact cleaners and other things which contaminate the little carbon contacts almost every keyboard uses underneath the rubber pads, and yes even the slightest particle of anything can cause a key to not work if works its way into the carbon contact. The carbon deteriorates over time, I just did almost a complete replacement of the same carbon switches on an RM1X, and used new "clicky" switches that have no carbon contacts, but are a bit noisier. the old Alesis MIDI drum machines and midi sequencers used a carbon contact circuit board that I remember being horrible-deteriorated right away and was practically impossible to repair or restore.

[Geria]

The other day I was playing the WK-7500 using headphones. My wife interrupted me saying that I was making too much noise hitting the keys. I am finding out that after a couple of years the keys are becoming noisier. Even a slight keystroke for pianissimo is noisy. Has anyone experienced this? Can it be corrected? All my Yamaha and Roland keyboards had felt strips. Would that help?

[Jokeyman123]

Check out my other posts about this. I haven't worked on the WKs, but both my XW-P1 and PX-350 keyboards have one long felt strip inside under the keys located directly where the keys contact the body of both instruments. It is very thin and yours is probably now so compressed from playing, it is almost directly hitting plastic on plastic, if the WK is similar to the XW and PX-350. since the body is hollow and plastic, it amplifies the sound when the key strikes it.

 

I found it necessary to add felt underneath not just to reduce key clatter but because the shock at key bottom was very hard on my hands (I play with a fairly heavy touch since I trained on acoustic pianos, old Wurlitzers and Fender Rhodes-very heavy keys). It's a difficult mod, requires alot of disassembly and much patience-if you know a good keyboard tech I'd recommend that. if you are up to it, look up the other posts here, I have a detailed post about how I did this with the XW.

 

If key clatter is from the return/up stroke-kind of noisy on the PX350 there isn't much you can do. When a key springs back, there are tabs that hit little felt stoppers in between each key. If worn, you have to add pieces of felt between each key-a horrifying prospect to me at least and not worth the trouble. Hope this helps.

[Geria]

Peeked in between a couple of keys using a strong LED torch. Did not see any felt strip, but noticed some white irregular material. Used a toothpick and brought up white grease with fiber strands. So your assumption is correct. There seem to be felt pieces under the keys. Why the grease, I have no clue. I better leave things alone, turn up the volume when practicing and move the instrument to a different place so my wife does not hear the clatter of the keys. It is not bothersome when performing, especially with the speakers turned on and using an amplifier. Can't have it all for the price of this keyboard.