Modern electronics with microsized surface mount components and multi-layer boards just can't be reliably repaired by a DIYer. Furthermore you need diagnostic equipment and information that simply isn't either affordable or available to the average guy. So I simply replace "boxes" when they die. There was a time when I repaired those components (including computers), but that was a Looooong time ago when the individual components (resistors, caps, inductors, diodes, chips, etc.) were big enough to see and even pick up