. ▁On ▁pract ically ▁all ▁original ▁Apple ▁Des ktop ▁Bus ▁systems , ▁it ▁is ▁not ▁safe ▁to ▁plug ▁in ▁or ▁un pl ug ▁a ▁device ▁once ▁the ▁system ▁is ▁power ed ▁on ▁( un like ▁modern - day ▁b uss es ▁designed ▁with ▁hot - swap ▁in ▁mind ). ▁This ▁can ▁cause ▁the ▁opening ▁of ▁a ▁sol der ed - in ▁f use ▁on ▁the ▁mother board . ▁If ▁brought ▁to ▁an ▁author ised ▁deal er , ▁this ▁can ▁result ▁in ▁a ▁mother board ▁swap ▁at ▁a ▁significant ▁exp ense . ▁A ▁simple ▁alternative ▁is ▁to ▁obtain ▁a ▁f use ▁at ▁a ▁nom inal ▁cost ▁and ▁wire ▁it ▁in ▁parallel ▁across ▁the ▁open ▁mother board ▁f use ▁( not ▁even ▁necessarily ▁requiring ▁sol der ing ). ▁ ▁Pat ents ▁▁▁▁ 4 , 8 7 5 , 1 5 8 ▁Ash kin ; ▁Peter ▁B . ▁( Los ▁G atos , ▁CA ), ▁Clark ; ▁Michael ▁( G l end ale , ▁CA ) ▁▁ 4 , 9 1 0 , 6 5 5 ▁Ash kin ; ▁Peter ▁B . ▁( Los ▁G atos , ▁CA ), ▁Clark ; ▁Michael ▁( G l end ale , ▁CA ) ▁▁ 4 , 9 1 2 , 6 2 7 ▁Ash kin ; ▁Peter ▁B . ▁( Los ▁G atos , ▁CA ), ▁Clark ; ▁Michael ▁( G l end ale , ▁CA ) ▁▁ 4 , 9 1 8 , 5 9 8 ▁Ash kin ; ▁Peter ▁B . ▁( Los ▁G atos , ▁CA