Not sure where you can buy original elements, except maybe a CB shop. There is a Ham radio operator, W2ENY, sells replacement kits using an Electret element on Ebay. You can google W2ENY and find his website. A more interesting solution maybe W9AC who designed a replacement board, which is available on Oshpark. I googled W9AC D104 and found several documents on his board.
Dave
k4em
