Piano Keys very low volume

Question

Yamaha DGX-640

Yamaha Portable Grand Piano DGX-640.

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KaitoKozo @kaitojzy

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crwdns2931729:0crwdne2931729:0: Mud 31, 2024

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Piano Keys very low volume

I tried to use my old DGX 640, but it had a first issue with no sound output at all. Referencing https://www.youtube.com/watch?v=PLPNpbFG... , I had the similar faulty capacitor C207. After replacing it, my piano how has normal volume audio output for all pre-sets, metronome, etc. However, any sound generated from the keys themselves are extremely soft. The volume of the keys when set to 100% output is as loud as the metronome at 10% volume. I'm not too sure what else I should try to check next to rectify the low volume from the keyboard itself.

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jayeff @jayeff

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crwdns2931729:0crwdne2931729:0: Mud 31, 2024

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Hi @kaitojzy

Try resetting the grand piano back to factory default and check if that resolves the problem.

Turn off the piano if it is on and then press and hold the rightmost white key on the keyboard. Whilst still holding the key, turn on the piano. Once the power is on, release the key. The piano should then initialize back to its default settings.

Don't know the piano but did you check the settings as shown on p.87 of the user guide or aren't these applicable to the keys?

Looking at the service manual the audio amp is common as all the audio comes from the CPU, there doesn't seem to be any separate inputs into the audio amp - see the block diagram on p.8 of 67 for a simplified connection block diagram.

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Hi @jayeff, thanks for the assistance. Have tried factory resetting but still persists.

Even when I max out all the various volume settings, the keyboard is still extremely soft.

I'm wondering whether there's a signal path from the board that receives the inputs from the keyboards before routing it into either the CPU or the Amp, as the low volume seems very exclusive to the inputs from the keyboard only.

I'm not very apt at deciphering the various circuit due to lack of exposure, but I'm hoping to try to get some additional feedback that may further aid my troubleshooting

crwdns2934271:0Mud 31, 2024crwdnd2934271:0 KaitoKozo crwdne2934271:0

@kaitojzy

The keys operating sends a signal to the CPU on the wires appropriate to the desired note(s) being played, so that the CPU knows what frequency signal has to be sent to the amp simulating the frequency of the note.

Looking at the wiring diagram on p.66 of 67, the keys connect to the CPU (see SWX02 board with CPU in the middle and the keys connect directly to it via the GHL88M <page 2 14> connector cable).

There must be something else telling it to tone down the notes, either a setting or a control function somewhere

crwdns2934271:0Mud 31, 2024crwdnd2934271:0 jayeff crwdne2934271:0

@jayeff thanks for the insights, I think it is actually working as intended, just the old speakers either have a very low power or I'm just that unskilled. After comparing the volume of the music output and the maximum volume of me pressing the keys hard, they somewhat tally. I'll just take it as there was no issue to begin with, but sincere thanks for the assistance!

crwdns2934271:0Mud 31, 2024crwdnd2934271:0 KaitoKozo crwdne2934271:0

crwdns2934285:0crwdne2934285:0

Hi @jayeff, thanks for the assistance. Have tried factory resetting but still persists.

Even when I max out all the various volume settings, the keyboard is still extremely soft.

I'm wondering whether there's a signal path from the board that receives the inputs from the keyboards before routing it into either the CPU or the Amp, as the low volume seems very exclusive to the inputs from the keyboard only.

I'm not very apt at deciphering the various circuit due to lack of exposure, but I'm hoping to try to get some additional feedback that may further aid my troubleshooting — KaitoKozo
@kaitojzy

The keys operating sends a signal to the CPU on the wires appropriate to the desired note(s) being played, so that the CPU knows what frequency signal has to be sent to the amp simulating the frequency of the note.

Looking at the wiring diagram on p.66 of 67, the keys connect to the CPU (see SWX02 board with CPU in the middle and the keys connect directly to it via the GHL88M <page 2 14> connector cable).

There must be something else telling it to tone down the notes, either a setting or a control function somewhere — jayeff
@jayeff thanks for the insights, I think it is actually working as intended, just the old speakers either have a very low power or I'm just that unskilled. After comparing the volume of the music output and the maximum volume of me pressing the keys hard, they somewhat tally. I'll just take it as there was no issue to begin with, but sincere thanks for the assistance! — KaitoKozo

Yamaha DGX-640

Piano Keys very low volume

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