There are 3 options, you could contact Mike Koste at “Gobs of Knobs” here: for a used one. Or if he doesn’t have one, Renovated Radios might have a reproduction. Ed Schutz makes reproduction parts for radios here:
http://www.renovatedradios.com/index.php Both are in the U.S.A.
You could also post a WTB on the Antique Radio Forum here:
Hope this helps…