The N.Z. Vintage Radio Project

4 valves and a silicon bridge rectifier.  Around this time Bell switched to transistors and there were no further valve-based Colts produced - this was the last model with the warm glow.

Generally easily spotted by the black-painted badge riveted on the rear.  There is space for a model code on this badge, but no examples have yet been seen with the code stamped in.  The other identifying feature is the power transformer being mounted on an angle.