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MusicTech14, Technician
Category: Electronic Musical Instruments
Satisfied Customers: 419
Experience:  20 yrs experience in service & support of music instruments
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We have a Yamaha Portable Grand DGX 505, it is several

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We have a Yamaha Portable Grand DGX 505, it is several years old and has recently started playing some notes wrong. It seems to affect only certain keys but has the same affect in each octave e.g. the C plays much louder than the neighbouring keys.
Please can you advise what it wrong?
Hello and thank you for your question.Each key has two switches underneath it. One switch triggers slightly before the other. The piano's brain can calculate how hard a key is hit by measureing the time between the two switches triggering. When a key plays at full volume all the time it is a sign that the first of the two switches is not working. If the key doesn't play at all, it is a sign that the second switch is not working.The switch mechanism consists of strips of rubber bubbles, with conductive discs inside them, mounted over a circuit board with matching contacts. Pressing a key presses the bubble down onto the board causing the switch contacts to close. Cleaning the contacts may be all that is needed, but sometimes the rubber strip needs to be replaced. These types of switches can fail for a number of reasons: Normal wear of the conductive surfaces, tarnish, debris blocking a contact, or rarely a rubber bubble tears. Replacement strips are available. From Yamaha or various parts distributors.They look like this - I would recommend taking the piano to a local Yamaha service center to have it professionally serviced. Use the service locator at to find the nearest authorized Yamaha service center.I hope that helps. Let me know if you have any questions about this issue.
I still recommend professional service. However, if you are inclined and capable of working on these types of devices yourself, you may find it helpful to download the service manual.
Customer: replied 2 years ago.
Hi, thanks for your help so far. We have found a local service center but first are going to try some cautious diy, this will be in a couple of days time due to work commitments. Hopefully I can get back to you then if we encounter any problems?
Absolutely. Just come back to this page and post a response.
MusicTech14 and other Electronic Musical Instruments Specialists are ready to help you
Customer: replied 2 years ago.
I was asked to rate your service this morning, which I have done. Later today my son and I will taking a look to see if we can fix the keyboard. Hopefully I can still get back to you with any questions - or just to let you know how it has gone?