After starting this thread, I did a web search for "Blaupunkt radio parts"
which found Continental Imports, 1219 S. Main St, Gainesville, FL 32601,
352-377-6604, firstname.lastname@example.org. Stephen Brotherton from there
responded promptly by email that he had the new volume control. I phoned him
and ordered the part ($15.00) which I received promptly and after
installation my radio is back to normal. The installation itself is fairly
tedious so you might want to discuss having Continental Imports do the work
for you. They are an authorized Blaupunkt (and Bosch and Becker) service