Here's a neat instruction book I got with a 630-type set. Sadly, the set was in such bad shape I had to scrap it, one of the few old televisions I've ever junked. I kept the chassis for parts. Increasing the screen size from the standard 10 inches was apparently a popular "hot rodding" option for the technically inclined back in the fifties.
--Dave
630_conversion_p01.jpg
630_conversion_p02.jpg
630_conversion_p03.jpg
630_conversion_p04.jpg
630_conversion_p05.jpg
630_conversion_p06.jpg
630_conversion_p07.jpg
630_conversion_p08.jpg
630_conversion_schematic1.jpg
630_conversion_schematic2.jpg