SMALL CHIP BOARD AND LIGHTS FOR DD40AX

[ENGRET94]

Evening all. I have questions concerning my DD40AX locos.
I have one each of these locos, without sound and sound. I am converting my non-sound to sound. I have been able to purchase the main sound board thru Bachmann but am puzzled as to where I can find the small board that have coils on it or do I even need it to prevent burning out the main decoder board. I am using the loco that is sound equipped as my reference as I knew there would be subtle differences but I was able to mill the non-sound frame to hold the new sound board and the pins that hold the front strobe light board and the rear light board. I also need to know where I can get the two light boards fore mentioned. since apparently they do'nt answer their E-MAILS that we send to them. Any answers are appreciated . Thanks.