Re. difference of "screen" brightness of Pronto: I have two new Pronto remotes (black, blue, green, blue-green, or whatever YOU see--dark vs silver, ok?). The illumination of the screen is very much different in brightness in the two. Serial #: 37964843-brighter Serial #: 37974458-dimmer These were compared carefully in a dark room at night. Neither of the units had an operative light sensor. Both AA batteries and NiMh batteries were used and exchanged in each unit, after the batteries were checked with a volt meter. (All of the voltages were as expected from known specs.) The unit with the lower number was obviously brighter under all testing conditions to a degree that a faulty interpretation would have been impossible. Others observed the same result. Two silver units were examined. However, the owner refused removal of the AA tray for serial number "fearing" some harm could be encountered--sorry, but they did belong to him. They were both like the dimmer version of the "dark" unit. Maybe too few units were in the sample to make any conclusion that would flaw scientific methodology, however, differences were apparent to several people in the units examined. Be sure that I am positive the unit with the LOWER # was brighter, just so that there is no mistake here! By the way no "buzzing" was apparent to the observers in any unit. Both of my "dark" units have performed without flaw using either source of power in doing the normal range of Pronto use. THX-Daniel?