Fellow in Texas reproduced these several years ago. I bought a set for my 51J4. J4 went away and drive and knob set stayed. Will sell for $200 plus shipping which is less than I have in it. Will take Paypal. Thanx Lloyd Godsey KK7IZ kk7iz at cox.net 480-620-7145 http://www.lloydsdipsydumpster.com/ http://antiqueradioarchives.com/