When I had my ex-282 serviced, I also had the NAPSC serviced. The latter was not all that expensive. I was also doing service and DR upgrades on a HC2 and 250-2 at the time.
I recently had problems with sound just through one speaker. I took all of my Naim boxes to Class A, I was told the problem was the NAPSC, I was told this is rare but based on my experience a service would be good for your peace of mind. It wasn’t an expensive repair but missed listening to records fo a week or so.