Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>" <CTCDW-at-aol-dot-com> could be many things, but I have had the same problem when my coils were out of tune, usually severely. I have also encountered the same problem with too large a toroid for the power applied, but a breakout rod (shaped to a point) enabled and arc to form. Chris W