I have purchased a used Intregra Research RDC-7 and am waiting for it's arrival. All I know is that it is in "Great Shape" I also own a Aragon 4004 MKII which I have had for 15 trouble free years. But maybe now is a good time to haul them both into the shop for services. What attention should I make sure these units receive? Aragon was re-capped at some point but have no idea when.