jsg@aero.ARPA (Jeffrey S. Gruszynski) (09/23/85)
Actually the ringing is from magnetostriction of the flyback core. With voltages ~10KV the effect can be pronounced. Apply some flyback HV "goop", it should help. About all you can do is try to muffle it and/or wish the designer had used a better designed (more expensive) flyback.