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What Is Wrong With This Digital Piano Circuit Board Pic

What diode is used under the touch contact pad of digital pianos?

One of the Key in my PX-720 Casio Digital Piano is not working. I opened it and found that under the touch contact pad circuit board there is a defective diode (I swapped the diodes of the other keys with the defective one and it worked; all the keys have the same diodes)

I am not sure if this is a Zener diode, I tried to test it if it is a Zener diode using my own tools reverse biasing it to a 36V DC battery with 4k ohms resistor but my multimeter reading across the diode in a reverse bias is 36V, the Zener diode may be higher than the source but I believe that it should have a lower voltage since the cable connected in the circuit board says it is only 30V cable. (Cable E118147).

I am not very familiar with other types of diodes, please help me. The diode has a Yellow band followed by a transparent space in the middle like a Zener diode.

What is the difference between a piano and a keyboard?

Thanks for the A2A!Basically one is an ingredient or principal component of the other.  Like flour is to a cake; such is a keyboard to a piano.  The keyboard......is a part of a piano. The keyboard... ...is also a part of an organ.And most electronic synth instruments that contain a keyboard... ...are simply called a "Keyboard".The term "keyboard"; though still used to describe the row of keys traditionally struck by the fingers to impart thrust on the corresponding hammers and subsequently the corresponding strings; nowadays usually refers to an electronic "keyboard" capable of more sounds or tones than a traditional piano.  When someone says they're a "keyboard player" they typically mean they play more than just the piano.  There are so many synth tones that have no physical instrumental equivalent (and most: though not all: synthesizers utilize a traditional piano/organ keyboard as an interface) that they are typically lumped into "keyboard" as an instrument.  So in short, a "piano" typically describes an instrument whose sole sound generation consists of tones reminiscent of traditional piano sounds whereas a "keyboard" typically describes an instrument whose tones consist of any number of piano/organ/brass/string/wind/percussion/voice/synth tones. At least that's been my experience.

How can I connect to ground in a simple breadboard?

Power rails of breadboard are connected to your supply terminals.And if you know about breadboard whole of the power rail(vertical line to which red or black wire is connected) are at the same poetial .Grounding elements of circuit means connecting the elements to common potenial i.e reference node or just simply connect one terminal of your element to to black wire potenial refering to my circuit(whatever element you need to ground its one terminal should be connected to the black wire connected rail)Normally we take the negetive of battery as the ground potential or reference potential.enjoy :)

What are the advantages of using an Arduino over just using the underlying microcontroller?

I agree with both posts above, but having used both, I can definitely say there are benefits to just using the underlying microcontroller.The main benefit is faster code.  Depending on the compiler you use, your code can be a lot more efficient, because you're not required to use the framework someone else to wrote to make life easier.  Sure there are times writing your own USB driver is impossible, but there are times you just want something simple and fast.The second benefit is that you really understand what's going on.  But that's also more work.  You will know which registers control which functions, and truly appreciate the engineering that has gone into the modern microcontroller.But if you want high-level functions, such as a real-time operating system, you should go with something already made.

How do I make a circuit of L7909cv regulator?

You are really looking in the wrong place. If you just google L7909CV schematic you’ll get farther faster. 2Pcs L7909CV ST -9V 1.5A Negative Voltage Regulator TO220 LM PIC AVR Arduino | eBayhttp://www.mouser.com/ds/2/389/s...

How do I fix speakers that make a static sound only when there is no audio output?

From your description, it seems that the circuitry which detects whether or not there is audio signal coming in is faulty. Many active speaker manufacturers feel the need to implement an auto on/off feature, that you can't even bypass! I'd rather have a simple ON (I want to listen to music, even with 2 minutes of silence in between songs if I so wish) and OFF (I don't want to listen to music). Simples.Sorry, but I don't think there's anything I could recommend to fix this, apart from the usual suspects: electrolytic capacitors gone dry. If you know a bit about soldering and electronics, open up the speaker - POWER CORD DISCONNECTED - and use your nose first. Does anything smell like it's burnt? Do any components, or parts of the circuit board tracks, look charred?Then use you eyes: do any of the electrolytic capacitors (cylindrical-shaped thingies) look bloated, either at the top - it should be flat - or on the sides?If so, then jot down the values written on the side (capacity and voltage rating) and go buy some new ones.You wouldn't believe the high percentage of electronics that fail because of cheap capacitors mounted too close to heat sinks - making them go dry prematurely. Poor design.Hope this helps!