When I go to play a chord on my clavinova it plays a C chord with that note. For example, If I go to play a F chord, it plays F/c instead of just F! it's really annoying! can anyone help me please?

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.

it can be repaired or replaced if the boards are still available
Take it to an authorized service to have it repaired and failing that some shops that repair micro wave ovens have the technical ability to repair items of this nature
may be a good radio technician or radio repair shop could also do the repair as it is basically an electronic ( wireless/radio) that is controlled by keys

Check you have selected 'sync start'. The ACMP selection activates the automatic chords but not the rhythm, so each note produces a droning chord. Sync start activates the automatic chords and rhythm you have selected when you play anywhere near the bottom end of the keyboard. Alternatively you can manually press play to start the drums by themselves and then the chords will begin the moment to play with your left hand.

Try resetting the piano.

Hi
I'm not sure I completely understand your problem but......it sounds like you might be in "Fingered On Bass" mode. This means if you play a chord like F using the notes FAC- if you play them in 2nd inversion (so the order is CFA) the psr-1000 will make the note "C" the bass note. In this mode if you played ACF then "A" would be in the bass part. Change to "Fingered Chord"-this will enable you to play any chord with the tonic (the name of the chord) F whether you play FAC, ACF or CFA in the bass part. I don't have access to a psr-1000 but often with Yamaha instruments this can be changed by pressing and holding the "Auto Accompaniment" button. I hope this helps.
Musicwez

Verify that one of the automatic chord modes is not active. If you find other combinations triggering other notes, download this scvhematic showing TYPICAL Casio key matrix scanning:

http://elektrotanya.com/casio_wk-1200.pdf/download.html

The matrix is shown on page 5. It could be one of the disconnect diodes has failed. These diodes shown below the matrix on page 5 prevent crossing between multiple notes held during scanning so each can be individually scanned. Not there are TWO contacts per key and this is used to sense key velocity as one closes before the other.

#0031 DGX-630/YPG-635

Hi here is the manual of your Yamaha

techbelkin

NORMALLY "fingered" mode means that you have to "finger" the chord, that is, play all the notes of the chord. It sounds like it IS working as designed.

Hi ...
There are flexible cables that connect the keys to the main electronics. The connectors for those cables sometimes age poorly..
It is fixable. But dont "get taken" on a repair.
If it's just resoldering a few points,it shouldnt be more than $100.00
to fix