Hi audiosexers,
I want to replace the sustain pedal of my low end digital piano Casio CDP 130.

To my surprise, it's not a simple on-off switch, but instead, when pressed gives 130 ohm (!?).

Now, beside the obscure reason behind this kind of logic for a simple boolean trigger, I would like test it with a common pedal switch, but I fear to damage the keyboard.

So, does anyone own a CASIO piano and tried the thing?

Thanks

 

Last edited: Jan 8, 2019

Well for a Casio CDP 130 pedal to give 130 ohm seems right on the dot to me

[EDIT:] I've come back to say sorry, that was a stupid remark desperately trying to be funny. Pologize.

 

Thank you, but I have already an high quality Yamaha piano pedal, and that's why I wanted to replace that crappy Casio. But Yamaha is a simple switch, as it should always be (except for the half pedals).

 

Yeah, it' actually 129.8 ohm, they failed by 0.2

 

My experience with pedals recently has shown them to be a not an ordinary on off switch but rather the type of conductive pad that you would find under the keys on a piano keyboard or even an ordinary qwerty. The resistance you get will be higher if the pedal is older and dirtier. I recently bought a second hand m-audio keystation 88. After testing that all the keys worked including velocity, I was disappointed to see that the sustain pedal was not working. Suspecting it might be the pedal, and having no equipment with me, I plugged a guitar lead into the sustain socket and shorted the tip and sleeve on the other end with a guitar string that the seller had to hand and it worked perfectly. Getting the old pedal home it had certainly gone high resistance, it just needed the pad and contacts cleaning. I suspect that the 130 ohm is a limitation of the pad technology rather than a prerequisite of your casio or that it is just dirty. Have you measured your yamaha pedal to see if that is indeed a zero resistance switch.? If it is and you are still worried, you could always solder a 130 ohm resistor in series inside the pedal but personally I think it will be fine. I ended up using an on off switch type on my keystation.

 

Yes, Yamaha pedal is a pure switch.

Casio pedal was giving 130 ohm since the first use, so I think that it could be a selling strategy to force proprietary products.

I'm tempted to test the piano with a switch, but I'm still too afraid that something could burn, and yet your experience with your keystation is promising.

I may even try with a variable resistance and gradually lower it to see what it happens.

I'll try in future, but at the moment I'm not in that pressing urge, for now I can still use the crappy Casio pedal.

 

I have an update about this question.
Yesterday the sustain pedal quit its duty, so, nothing to lose, I decided to open it to investigate.

At the end I found that yes, it is a conductive pad, the same type you would find in a TV remote pcb, that would justify the 100+ ohm value.
It is inside a thin rubber cap that is pushed by the upper pedal, the rubber cap wore out and split.

I glued it with silicon and now it works again, however the piano sustain works fine also with a short, that means that any pedal switch is good.

No need for apologizes with no offence at all!

 

Why not solder an adapter? You could use a little extension cable and solder a 130 ohm resistor in there. Now you could plug any pedal and it would be within the specs.

 

That honors you.

Well my, I was offended!
Just joking of course

 

My guess is that the 100+ ohm value (it changes from time to time, 150, 120, etc.) is not a spec requirement but a tolerated effect due to lite/poor contact. As I said, when I short it the piano sustain still works.