I have just finished a service on a nice Linn Sondek LP12. This involved a thorough clean, fresh bearing oil, fitting a new cartridge, careful arm set-up and some suspension adjustments.
Setting up a Linn Sondek requires a little patience. One issue I find is that owners have often made modifications or had someone else make them. These have often not been done very well and can lead to trouble.
There is also a lot of what I would call audio “black art” surrounding the Linn. They work just like any other belt-drive deck and they really are not mysterious or even particularly great. They are a good though for someone who wants to buy into the legend, but for others who can see and hear past the rhetoric, there is better bang for your audio buck to be found elsewhere.
Anyway, the owner is very happy and that makes me happy! I am not an authorized service agent for Linn products, but I am happy to assist with servicing for owners of Linn turntables. I would suggest that if substantial work is required, or if you have a warranty issue, that you chat with the authorized service agent who is also a good friend of mine.