Eaks and Cambridge stand at 11-under-par 133. Brad Bryant, a Nationwide and PGA Tour alum, posted a 69 and is joined in a tie for third place at 9-under-par 135 by Hajime Meshiai (68) and Mike Malaska (67). First-round leader Mike San Filippo is alone in sixth place at minus-8.
Cambridge, a native of Jamaica, caught fire down the stretch as he birdied six of his last eight holes to close a back-nine of 6-under 30.
'I made a 30-foot birdie putt at No. 12 and then followed with another nice birdie at No. 13, which really got things going for me,' said Cambridge, who in four years on the European Seniors Tour has four wins. 'I also made a nice birdie at No. 15.'
Eaks played in seven events on the Champions Tour in 2004, but managed just three top-25 finishes. He got off to quick start with five birdies over his opening eight holes. He later erased a bogey on 17 with a birdie at the last to share the lead.
'I got off to a great start today, just a wonderful way to begin the round,' said Eaks. 'I made an 18-footer on the first hole and it's a great way to get things started.'
Des Smyth posted a 4-under 68 to move into a tie for seventh. Smyth stands at 7-under-par 137 and is joined there by Tom McKnight, Mark Johnson, Bobby Lincoln and Bob Cameron. Tony Peterson and Jay Overton were one stroke further back at minus-six.
Former major league pitcher Rick Rhoden carded his second straight even-par 72 and is tied for 48th place.
Seven players will walk away with full exemptions for the 2005 Champions Tour season, and eight more will receive conditional status.
For the first time, the tournament is being contested over 108 holes. The field will be cut after four rounds to the low 70 and ties, plus any additional players who remain within 10 shots of the 15th position.