I recently helped a friend to repair a Linn Valhalla power supply pcb. It would seem that these are prone to particular failures and a common one is low motor torque in which the motor buzzes or vibrates since it is too weak to drive the platter. This turned out to be R32 (560k) on the board. R33 had also deteriorated with the ceramic body breaking up. I have uploaded the circuit as a png and pdf file which some may find useful.
If you are having motor problems I would first replace these 2 resistors R32 and R33. Failing that then the next step is to replace the small orange caps around the logic chips if the motor does not turn at all.
If the unit will not power up then some early Valhalla units could blow the bridge rectifier so you will need to test this and the large power supply caps it feeds, assuming the fuse is ok. If the bridge has part blown then AC can reach the caps and damage them. If replacing any parts then consider using something slightly higher rated and higher quality as the standard parts are nothing special.
** Main circuit inside zip file download below **