Due to heavy rains, the wood chips lying on the #1 Reclaim Circulating Chip Conveyor became saturated and heavy to the extent that the weight yanked the gear box from the structural base. In order to make repairs, a maintenance employee was manually moving the gearbox chain tooth by tooth. When he released the chain on the third tooth/notch, he had his ring finger between the chain and the sprocket when the chain jumped causing his finger to be pinched. As the pinch was occurring, the employee pulled his finger back, which caused the skin to be removed at the tip of his finger. The incident resulted in the amputation of the fingertip.