What was found
AIRCRAFT WAS GROUNDED: APPROXIMATELY 10,000 FEET AFTER TAKE OFF, THE DISPLAY SOURCE 1 LIGHT ILLUMINATED ON BOTH PILOT PFD'S THEN EXTINGUISHED AFTER APPROXIMATELY 20 SECONDS. LESS THAN A MINUTE LATER THE DISPLAY SOURCE ILLUMINATED AGAIN ON BOTH SIDES ACCOMPANIED BY BOTH EEC'S TOALTN MODE. THEY ALL EXTINGUISHED APPROXIMATELY AFTER ABOUT 2 MINUTES FOR REMAINDER OF FLIGHT. BROUGHT UP HYD PAGE AND SYS A WAS 74 AND SYS B WAS 86. DECESION MADE TO DIVERT TO PNS, EMERGENCY WAS DECLARED AND AIRCRAFT LANDED OVERWEIGHT WITHOUT ISSUE. MAINTENANCE REPLACED DEU 1 IAW AMM 31-62-21-400-801.