When watching live TV on my Roamio Plus (6 tuners), I use the INFO button followed by DOWN to show a list of channels that are active on the tuners. Those with a red dot are currently recording, while those with a gray dot are only buffering. Using RIGHT and UP/DOWN lets you select a tuner if you want to switch. Tuners that are in use by a Mini are marked "In use by ...." and can't be selected from the tuner list. No, the tuners in the TiVo are always active (ignoring standby). My TiVos are configured so that hitting the TiVo button puts the live TV in a small window in the upper/right corner of the screen, so tuner allocation doesn't change by hitting the TiVo button. Use the tuner list, as described above. While watching live TV, hit INFO and DOWN to display the tuner list.