Karavite, thanks for your thoughtful comments. Hopefully, you won't need service anytime soon, because Scott designed these units for very long tube life. My understanding is that their policy is to bias tubes at about 75% of recommended voltage. They must have done something right, because so many of these units built at least 40 years ago are still in circulation, still in demand and still making music. Some units even have their original tubes.
I second Linnlp12's prudent thinking about not changing resistors (or other parts) unnecessarily. It has been my experience that with components designed around older parts, whether guitar amps or stereo equipment, mixing in new components for modification or repair sometimes takes away from what you liked about the unit. If you have leaky caps or other problems, you do what you have to, but otherwise I think it is best leave things alone as long as possible. A Scott engineer was quoted as saying "if it measures well but sounds bad, it is bad. If it measures badly but sounds good, then you have measured the wrong thing." I think that like the people at Linn, they listened carefully, and that is what makes their stuff sound so good.
I second Linnlp12's prudent thinking about not changing resistors (or other parts) unnecessarily. It has been my experience that with components designed around older parts, whether guitar amps or stereo equipment, mixing in new components for modification or repair sometimes takes away from what you liked about the unit. If you have leaky caps or other problems, you do what you have to, but otherwise I think it is best leave things alone as long as possible. A Scott engineer was quoted as saying "if it measures well but sounds bad, it is bad. If it measures badly but sounds good, then you have measured the wrong thing." I think that like the people at Linn, they listened carefully, and that is what makes their stuff sound so good.