The Tascam 42NB is too new a product to worry about recapping at this time. Maybe in another 15 years there will be occasion to find a common cap problem on them. It seems to me that people do the opposite of what is right. They never want to recap Vietnam era decks and then here comes a 42NB or BR20 and they want to recap those. Lets use logic and some level of predictability of the failure of these parts as too many are wasting time with unnecessary practices. I can not remember a failed cap in a modern Tascam product but have experienced many failed parts in units of questionable component selection. Those would be the poor caps used in Technics RS decks and those that used 10V caps in cassette deck and even the Z7000. I have had these parts short.
In most of the 42 deck I have worked on they needed very minor correction and most of the problems come from people that get under the splicing block to turn tensions with not the proper equipment and then of course the decayed rubber on Tachometer and Pinch Roller. Terry makes easy solutions to this and I always have him do the job. The other thing is they used plastic feet on these heavy decks that are really not up to the task.
Parts Express sells a rubber amplifier foot that even when kicked by accident the Tascam feet would break but the rubber ones stay put. The same rear feet are used on Otari decks as well. The Tascam 40 series decks as well as 50 and 60 are great machines to have and work on.