I don't know if he is still going, and I would guess probably not, but
there was a guy who did Becker and Blaupunkt transistor rebuilds named
Willie Wilkes. He used to be in Brisbane (Brisbin?) , Pennsylvania. He
rebuilt one of each for me brilliantly about five years ago. Nice, nice
man. Sorry that I can't be of more help, and if he is still going he
used to advertise periodically in Hemmings Motor News. Best 'O Luck.