[drh4683]

I've been trying to solve the 40BC50 mystery for quite some time, and with no success. The factory Zenith service manuals only provide a schematic, yet they do not provide a top view of the chassis or any of the additional chassis details or drawings as they do for every other chassis. I have a 1971 Zenith brochure and there are two models shown that supposedly use the 40BC50. These sets were higher end cabinets with bi-folding doors, which of course means all the emphasis is on the appearance of the cabinet, so they only show you what the set looks like with the doors closed. Go figure. So who knows what the escutcheon and control panels really looks like. The 40BC50 chassis also used an electronic tuner. It was a motor driven varactor type, but its mechanical design resembled that of a Zenith's Super Gold Video Guard (turret) tuner. This electro-mechanical varactor tuner incorporated a rotating drum channel indicator. It was a totally different set up compared to the vertical channel strip motor drive varactor tuners used on the more familiar D and E series flat chassis SS sets for '73 and '74 (respectively). I'm pretty sure that the 1972 25CC55 chassis only used conventional VHF turret and continuous UHF tuners. The only reason I know about the layout of this early electronic tuner for the 40BC50 is because Zenith took a picture of it for the brochure to show off the "latest and greatest" in tuner technology... The tuner appears to also have a very small tuning meter which was most likely used as a channel indicator for adjusting the channel presets. Very neat looking set up. Will anyone ever be lucky enough to find one? Who knows...