My CVP-7 sounds a little off in some of the settings. Would replacing the motherboard help?

A computer :>D

https://www.manualslib.com/manual/374549/Yamaha-Clavinova-Cvp-307.html?page=192

https://www.google.com/search?q=Yamaha+CVP-307+read+Midi+files

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Most Clavinovas can be removed from the stand by simply looking underneath and locating the fixing bolts. Yours will need lo be laid down onto the back edge, locate the bolts at the top of each leg, unlug any cabling for sustain, mains before laying down.
See attached

The Yamaha CVP-601 can be transported fully assembled. However, yes, it can be disassembled if desired.

Your owners/operators manual will detail the procedure.

Click here if you do not have one: Yamaha Clavinova CVP 601 Owner Manual Assembly Preparation Before...

You would be better off applying the cost of repair toward a new piano.

Possibly.
Depends what you mean by "off".
I know of an electric piano that sat in front of a window that leaked when it rained. Now the piano sounds like the vibrato is running at about 40 cps. It probably needs a new circuit board. But the owner doesn't notice it and he has no audience. "It sounds fine.", he tells me.
On the other hand, you may just have a lose part that physically vibrates inside somewhere when you play notes that resonate with it. It's hard to say without hearing it.

There is a well documented problem that occurs with the keybed on some of these models due to a manufacturing fault. Take a look at the keys that are sticking. Is the gap on either side of the key the same ? If not then the key normally leans slightly to the left rubbing on the adjacent key causing the sluggish action. The fixing tab at the back of the key breaks causing the spring pressure to push sideways.

You can just replace the offending key but the problem will eventually return. You could replace the whole keybed but this is a very expensive fix.

Keys are around £ 15.00 each.
Replacement keybeds around £ 450.00

Visit www.beckettsmusic.co.uk

Search for VU101 via the search box.

how opening yamaha cvp-700

Best thing is to go to Yamaha America in California and go through the parts department and ask for a service manual on CD. They USUALLY sell the CD for $15 which has all the service data including schematics.

This sounds like it MIGHT be a floppy drive problem rather than a full memory... REMEMBER to ONLY try recording a file no bigger than what the floppy will hold which is 720Kb.

NOTE: The disks used in this are not the COMMON 3.5 inch floppies, but the older 2DD 720K floppies. They have only one hole on corners where the new 1.44 Mb ones have two holes.

To USE the 1.44 Mb flopies do this: Use an opaque tape to cover the hole that does NOT have the write protect slider. THEN most omportantly DEGAUSS the disk with a degausser. THEN Reformat the disk in the CVP 65.

The pre-formatted 1.44 disk when formated at the 720Kb used by the CVP 65 will have ARTIFACTS between tracks since the higher density also have half the track spacing and the formatting doesn't always clean enough width leaving artifacts between the tracks when formatted as 720Kb These ARTIFACTS can cause trouble.

The 720Kb disks are ESSENTIALLY unavailable anymore.

I SUSPECT that the CVP 409 will ONLY talk to the Yamaha USB floppy drive, not a hard drive or memory stick.

The internal drivers for these musical instruments do not have the "smarts" to talk to the wide variety of peripherals that PC's are able to.