Would have to go with Hobbs on this one . Dissimilar metal contacts prone to issues .Old lead alloy solder works best where originally spec. ROHS ( reduction of hazardous substances ) has caused many issues during the transision . If you have Ham operators in your circle of friends they may come across some at " Hamfests " ( amateur radio shows ) . Also the generation that bought and built radios / TV ( heathkit ) are dying off . I source some of my organized electronic parts off the estate sales . Not bottom feeding just want to keep good parts out of landfill . When my time comes I hope my stuff goes to good use by others . Shane