I play a Yamaha motif xs8, and recently I’ve noticed that it will go out of tune.  It will start out fine, but during the course of playing, it will become out of tune.  Restarting the keyboard seems to fix the problem temporarily.  The problem seems to be getting worse and is happening more frequently.  How do I fix it?

Welcome to the forum.

Does the pitch shift if you lightly tap on the Pitch Bend wheel, without rotating it? Also, try turning the wheel back and forth several times and see if the condition improves.

Sorry for the delay in responding. It went out of tune again on me recently, and I had a brief moment to play with it. I may not be doing something as you instructed, but I didn’t hear a difference by just tapping on it. Moving the pitch wheel changed the pitch, but didn’t seem to improve the tuning. What do you suggest I do next?

Most such random pitch shifting is due to problems with the Pitch Bend control or connections to it. If tapping on the PB wheel itself doesn’t cause a shift while playing a note, see if tapping on the top panel of the XS near the PB causes a change.

If that doesn’t provide any clues…
Are there any MIDI connections (via DIN or USB)? If so, try temporarily disconnecting them when the problem occurs.

Is the power reliable? The XS is typically quite tolerant of voltage drops within a reasonable range, but it’s possible to have strange random occurrences if the voltage is significantly low.

Let us know. Depending on your reply, there might be other things that can be checked.