Schulz, 50, making his making his 12th Champions Tour start of the year, had never held a lead after 32 holes. He birdied the third and sixth holes to move to 12-under and then parred his final three holes to finish at 12-under 132 at Pebble Beach, Calif.
First-round leader Mark Calcavecchia stumbled to a 1-under 71 Saturday, falling into a tie for second place at minus-9. Tom Kite joined him there with a 4-under 68.
Calcavecchia moved to 10-under after he birdied No. 10. But then he bogeyed three of the next four holes to slide to minus-7 before carding birdies on the final two holes.
Holding sole possession of fourth place was Tom Pernice Jr. He shot a 70 to finish at 8-under-par 136.