It's quite strange how many people [of all ages] come to the Forum with the notion that changing lots of components is the way to go. I can only assume that it's from watching You Tube or maybe audio equipment restorations where the person carrying out the work is so familiar and experienced that they can get away with it and also actually trace any problems they've create from that themselves. I've never read anything re servicing/fault finding that said "first change all these as a matter of course". It wouldn't work on a car or in medicine would it-you have to figure out what may be wrong first
Less is more sprdsht!
Dave w