Piece of cake. I do this on live recordings, and THERE the drift can be BAD. I have to go section-by-section.
But your Tyros probably is just a bit slower.
 
Does the song end at a definite point or does it fade out?
 
If it ends at a definite point, trim the end of the clip to be exactly on the end of the last bar. Even with all of the autoaccomp playing at once, the downbeat should be clearly visible. Go one bar beyond that.
 
Next, if the Tyros is slower, shrink the track. If it is faster, stretch the track.

Many thanks.
What I do is record a general backing first as a guide, then add individual instruments one at a time (eventually losing the full auto accomp).
I will definitely try what you suggest, but as I record each instrument individually, I am not at all clear that this method will ever be exact enough for what I require. My attempts so far suggest that the pinpoint accuracy I have always enjoyed will be a thing of the past.
Does anyone know why my Tyros has SUDDENLY slowed down? Why now? And is it possible for me to adjust any settings within Tyros to put it right?

I think you are saying it's in time and then over a short period of time one tempo will change causing the whole thing to go out of sync. A simple stretch will only work when the tempo difference is constant.

It seems to me that either Sonar is "hickupping" or the Tyros is. Have you tried playing with the Tyros for an extended period of time, listening for hickups?
How are you monitoring when you're recording? Through Sonar or directly from the Tyros?

It seems that the Tyros 2 is no longer in time, albeit fractionally. But I don't know how to correct this.

If that really is the case it's time for the repair shop I'm afraid.

Expensive, do you know?

Let's see how much your Tyros' timer is out by.
 
This assumes the Tyros clock is running slow or fast. If it really is fluctuating, this won't help much.
 
1. Find the simplest beat you have. Best a rock 4/4. Set the rhythm to 120bpm.
 
2. Record 17 bars.
 
3. As accurately as you can, trim the beginning to the first bar. Zoom in as much as you need.
 
4. Visually count across 16 bars, zoom in to the first beat of the 17th bar and put the Now cursor on this first beat.
 
5. Go to Project > Set Measure/Beat at Now...
 
6. Enter Measure (17th measure) and beat (1st beat)
 
7. Hit OK and the beat displayed in Sonar is the actual tempo.
 
For more accuracy, record more measures.
 
If you have access to an electronic metronome, set that to 120, start both and see if the one catches up and passes the other. Could be the electronics in the Tyros is faulty, although it really should have a crystal, so that is worrying.
 
 
 

Is the meter (time signature) the same all the way through?

Okay: just to make sure... I am looking for the first beat of bar 17? (Yes, I will never win an award for musical brain of the year).

Yes, indeed it is.