Museum Hours:

Saturday 10-6

Sunday 12-5

Picture Tubes

RCA C73293C Developmental 3 Gun Color Tube

From RCA 1950 brochure

Here is a Popular Science Article an a Popular Mechanics Article about RCA developmental color tubes. Here is a photo of a set with this tube in operation. A similar tube was used in the RCA CPA prototype presently at the museum.

The following information is from Dave Abramson, owner of the only other C73293C:

There were only under two hundred of those and they were only let out to prospective licensees for examination or for engineering sets.  It is truly the first modern color picture tube. 

It is a variation of the 16" metal shell tubes in the RCA line.  The mask and phosphor assembly was in a separate front piece and aligned in a sort of light tunnel, then welded to the rear bell.  The weld ridge became the anode connection.  RCA went wrong from the beginning.

This tube was use in the tri-color models 1 and 2 and possibly the 2A.  Model 1 was the first RCA demo to the FCC.  These tubes were circa April, 1950 to February, 1952.  Models 3 and 3A used a 3-bolt version.  Starting with the 3, they improved the trajectory of the guide bolts for the shadow mask alignment.  The model 4 appears to be the first of the glass tubes.  Most of what I know can be found in the RCA Color TV submission to the FCC...the "red book"...and in the second "Proceedings of the IRE" on color television.

Three screws can be seen above and below the screen

This is the tube in John Folsom's CBS RX-89 prototype, with 3 screws located around the screen. It is probably the same tube used in the RCA model 3 receivers.

From RCA's 1952 Annual Report

Courtesy of Bob Dobush

RCA Radio Age, July 1951

Courtesy of Steve Dichter