Richard,

Skin heads have their own rules. They are quite sensitive to relative humidity. If you get too enthusiastic about winching the head up on a humid day, it might pop on a dry day. If you have a hair dryer you might want to apply it gently to the head to dry it out a bit and raise the bridge. I have reconciled myself the fact that there will be days when I will get no useful sound out of the instrument.

Russ (Permanent GUEST and banjo player)