Zenith 40bc50 mystery set

[AUdubon5425]

DRH4683 has been looking for one of those for as long as I've been reading this board. From what I remember of his research there's a good possibility they never made it into production.

[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...

[zeno]

A few notes on this. They must have built some,
but maybe they went to a select few & probably got called
back in after testing ala Chrysler turbine cars. Being in the line
folder they probably intended to release them but didnt for
an unknown reason. Bose sets were limited distribution at
first & probably the digital process chassis also, I cant remember.
Another thing that I noticed back then the parts for both the
digi set & projo were listed in the book way before we knew
about them. Wonder if 40bc50 only parts were listed ??

Varactor tuner: C-line intro
In the TM it dont look like a SGVG tuner. A small box with pots
that look a lot like the newer ones in a turret. Bandswitch cams
that work one bandswitch. Plasic part on front probably mounts
from front not back as the norm. On rear some gears & the
usual SC twist for stop or off setup. Motor hangs underneath.
Tuning meter & bandlamps shown off board in schematic.
Tuners were modern with FET RF amps on both U & V.
I worked at a Big Zenith dealer from 1970 on and never saw one
& we covered several very high end towns. C line SS set were
not common, most we sold & serviced were E line, lots of them
& they were plain fun to work on. (not so much the vert chassis)

73 Zeno

[AdamAnt316]

Not sure about the 40BC50, but the 25CC55-based Space Command console my grandparents had (sold to technicolor) sported the aforementioned bi-fold doors, and the motor-driven tuner (with a horizontal drum) involved a small meter with lights behind it, so maybe some details did survive. You might want to ask Joe about it.
-Adam

[zeno]

Originally Posted by AdamAnt316

Not sure about the 40BC50, but the 25CC55-based Space Command console my grandparents had (sold to technicolor) sported the aforementioned bi-fold doors, and the motor-driven tuner (with a horizontal drum) involved a small meter with lights behind it, so maybe some details did survive. You might want to ask Joe about it.
-Adam

I have the training manual for 25cc55, I described the tuner above.
Never seen one in person & not even a pix of the front, just
the guts. The set has to be super rare. You pay a premium for a
Zenith, doors, solid state, varactor tuners & remote. Had to be
$900-$1100 back then, a LOT of money. Never sold many door sets,
not popular & only on high end sets. At the end of the model year
we would buy some on close out cheap & usually removed the doors.

73 Zeno