Not all that familiar with BOSE's lineup, but did find these in my go to place for service manuals. Free to download (easier if you create an account).
I did download the L1 System 1 and it's a very comprehensive and detailed service manual. A good independent tech should be able to get these manuals easily if they try. BOSE 'may' have some proprietary components that only they can provide which may make it a challenge if needed.
https://elektrotanya.com/showresult?...all&page=1#res
.