Key plays too loud - Yamaha YDP223 Digital Piano

There is a dual contact strip under the keys that the hammer (key) hits from the hinge end. When the hammer hits, the time it takes to close both contacts determines the level of pressure and gives a quiet, (light) or loud (hard) and the processor knows how loud to reproduce the note/s.
If a contact is damaged, there will be no control of the volume.
Replace the conract strip and felt pad.

This link might help.

https://www.google.com/search?q=Casio+Privia+px-100%2C+loud+key

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What is your piano brand and type?
Damage to the contact rubber can cause note plays loudly or,
note does not plays at all.
It is caused by:
1. Carbon rubber contacts dirty / dusty (yellow arrow). Clean with a pencil eraser (or cloth). Gently rub it.



2. Contact rubber is torn (your case). If this happen,it can not be repaired or glue. So, you have to replace one octave.
The yellow arrow indicates the side that is often torn.

Rubber side that is torn, usually not seen, unless we move / pressing gently on top (In the rubber contact position is not installed on the board.)
Examples of this picture was yamaha psr.

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Below the keyboard, there is a rubber contact (see figure 1). Damage to the contact rubber can cause:
- Note plays loudly or
- Note does not plays at all.

It is caused by:

1. Carbon rubber contacts dirty / dusty (yellow arrow). Clean with a pencil eraser (or cloth). Gently rub it.

2. Contact shredded rubber. If this happen,it can not be repaired or glue. So, you have to replace one octave as in Figure 1.
The yellow arrow indicates the side that is often torn.

If you have any key note problems with your yamaha psr 9000 and need It repaired contact a qualified engineer at [email protected]

those bubble contact strips will have to be completely cleaned, when dirty
the keys will be at max velocity(loud).

If it is under warranty, may as well make use of it. In the long run it will be less headache for you.

It is something that should be repairable, although time consuming. as it is likely a stray bit of solder lodged where it should not be.

Of course it is repairable.

Find a competent repair person. You did not describe the "noise". If it is 60 cycle hum, the filter caps need replacing. If it is an organ tone, then probably a key contact is stuck.

I am sure it can be fixed. Who knows what brand or type of instrument this is...

The stuck keys are probably mechanical sticking. The loud keys are probably dirty key contacts that sense velocity.

Take unit in for servicing.