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Repair and disassembly guides for electronic keyboards.

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Yamaha p-45 keyboard with several keys not making sound

I have a Yamaha p-45 and currently first four d's ( lowest) and the first three a flats are not making sound. I have opened up the bottom and everything looks good, no corrosion or stray hairs getting in the way. Any suggestions?

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Hi,

I cannot find a circuit for a Yamaha P-45 but have found the service manual for a Yamaha P45-B which hopefully will be close enough to be of some help.

To download the file click on the “I am not a robot” checkbox and then select download. Be patient it takes a little while to find the file.

I don’t know about notes in music but looking at the circuit it appears that a +3.3V supply is fed to each note in the scale and when a key is pressed this voltage changes and the change is detected by the CPU and the appropriate note is played.

Since only the first 4 lower D notes don’t work it may be that there is a break in the wiring multiple or a loose connector to the section of the keyboard.

Check that the harness plugs between the DM board Connector 201 and the GHL88M board Connector 2 and the GHL88M board Connector 1 and the GHL88L board Connector 1 are securely connected and that there is +3.3V appearing on the appropriate pins as shown below The GHL88L, M and H boards may be directly below the keys

Here are some images where I have shown the location of the power supply circuit for the D notes.

click on images to enlarge for better viewing.

The power for the D notes is on wire N12

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and leaves the DM board on Connector 201 pin 27

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where it comes in on GHL88M (M for middle?) board Connector 2 pin 2 to feed the middle numbered D notes (D2-D4) and multipled to GHL88H Connector 3 pin 2 to feed the higher numbered D notes (D5-D6) as well as GHL88M board Connector 1 pin 17

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where it connects to GHL88L (L for left?) board Connector 1 pin 2 to feed the lower numbered D (D0-D1) notes

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Thanks for your reply, unfortunately it appears that this is above my level of expertise. Perhaps I can find a repair person that I can pass this information on to.

von

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Sarah Gage-Hunt wird auf ewig dankbar sein.
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