Casio Keyboard Playing Demo Tunes and changing instruments on its own.

[Lurch]

My keyboard will randomly start playing Demo Tunes and/or changing instrument Tone numbers on it's own, without any input from me. It will also do the same thing while I am practicing with it. I disassembled it down to the main circuit board and cleaned all of the circuit contacts and rubber buttons. A few days later it was doing the same thing. 

 

This same situation occurred about a year ago. I cleaned it as described above and it solved the problem until now. Has anyone ever heard of this happening and/or have any suggestions?

[CYBERYOGI =CO=Windler]

Possibly conductive liquid (battery acid, cola, salt water etc.) has flown inside and randomly shorts contacts. You may need to wash the PCB with water and dishwashing soap (rinse well, towel dry and possibly dry with hairdryer at low heat) to remove residues. Important is, do not connect to electricity/insert battery so long it is wet (else it corrodes) and keep the speakers dry (desolder them) because the diaphragm is likely paper that gets ruined by water.

 

But it may even be that your keyboard is not broken at all but reacts on strong electromagnetic fields e.g. by a nearby radio transmitter. Unlike the human brain, modern keyboards unlikely get messed up by mobile phone radiation, but if the keyboard is older than about year 2000 or there is something else (e.g. a high power HAM radio) transmitting nearby, it can freak out by that. E.g. the computer keyboard of my Amiga (built into a wooden custom cabinet) started to type random characters when teenagers in a room above mine used a CB radio. Moving the keyboard cable reduced sensitivity to it.

Edited November 29, 2022 by CYBERYOGI =CO=Windler

[Lurch]

very interesting. Now that you mention it could, high humidity / condensation do the same thing?

 

All contacts were recently cleaned with alcohol. The keyboard can go from ambient dry conditions (AC running) to humid conditions (No AC running) and back again? It can be an everyday situation where I am.

If so, how would I defend against that?

Edited November 29, 2022 by Lurch

[CYBERYOGI =CO=Windler]

When the keyboard is ice cold (e.g. left in a car in winter) and bought into a warm moist room, water can condense inside and short contacts of the keyboard matrix, which results in sensing wrong key and button presses.

 

I guess the situation needs to be a bit extreme to make it fail, but I own e.g. a Micronta - Vox Clock 2 talking alarm clock, which reset input of the sound CPU is so high resistance, that it crashes during high humidity (or when huffing moist air on the capacitor) and so only plays a pop/click noise instead of talking when the atmosphere is way too moist.

Edited November 29, 2022 by CYBERYOGI =CO=Windler

[Lurch]

I might add that the high humidity where I am at the moment is also very salty. My board is a wk-3200, purchased 2002 and it sits close among cell phones and wifi much of the time. Looks like I just have to try to minimize the effects and take not of humid/dry days. Thanks much. I'll check it out.

Edited November 29, 2022 by Lurch

[CYBERYOGI =CO=Windler]

Did it ever got wet by conductive (salty, sour, battery-) liquids? If the stuff is still on the PCB, it will later react more sensitive to moist air and corrode much easier if not removed.

[Lurch]

The keyboard never actually had anything liquid spilled on it. The most that happens is that the climate at the current location is very humid with salty air at times. (near the ocean). 

[Lurch]

update