YOU MUST BACK OFF THE ADJUSTERS COMPLETELY, THEN A SHARP TAP WITH A HAMMER ON THE FLAT SECTION OF THE DRUM (BETWEEN THE STUDS, TAKING CARE NOT TO HIT THE STUDS THEMSELVES) THIS WILL SEEM TO BE HAMMERING THE DRUM THE WRONG WAY, BUT IT SHOULD LOOSEN THE DRUM ENOUGH TO BE ABLE TO PULL IT OFF.
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