<P> General Electric (GE) had been working on a variety of systems that would allow them to introduce color sets that did not rely on the shadow mask patents . Through the 1950s they had put considerable effort into the Penetron concept, but were never able to make it work as a basic color television, and started looking for alternate arrangements . GE eventually improved on the basic shadow mask system with a simple change to layout . </P> <P> Instead of arranging the guns, and phosphors, in a triangle, their system arranged them side - by - side . This meant that the phosphors did not have to be displaced from each other in two directions, only one, which allowed much - simplified convergence adjustments of the three beams, compared to the conventional delta shadow mask tube . This differed sufficiently from RCA's design to allow GE to circumvent the patents . It is important to realize that the GE 11" tube still had round mask holes and phosphor dots, not rectangular ones as in the later slot - mask tubes . The innovation here was with the in - line guns as opposed to the triad arrangement . </P> <P> This change, which allowed vastly simpler convergence measures, together with the use of GE's own Compactron multi-function vacuum tubes led to reductions in size of the entire chassis . GE used the small size of their system as the primary selling feature . The original 28 pound set used a 11" tube and sold for $249, which was very inexpensive for a color set at that time . Introduced in 1966, the Porta - Color was extremely successful and led to a rush by other companies to introduce similar systems . GE continued refining this system, up until 1978, which marked the end of production of vacuum tube type television receivers . </P> <P> GE produced the basic Porta - Color design well into the 1970s, even after most companies had moved to solid state designs when transistors with the required power capabilities were introduced . The Porta Color II was their attempt at a solid state version, but did not see widespread sales . The basic technology, however, was copied into GE's entire lineup as product refresh cycles allowed . By the early 1970s most companies had introduced the "slot - mask" designs, including RCA . </P>

The ge model suggests a colored screen of