I just had a guy give me 4 old Altec 15" woofers. 1 works great 2 need work and the last one is dead. The problem is I can't find any information on them. The model # on the massive magnet is 20802 and they are 16ohm. I would like to repair the other 3 but can't match replacement parts to these model numbers. See attached pictures. Thanks for any help.