What was found
DEN - FLT 655 - AFTER TAKEOFF GEAR RETRACTED, SPOILER LOCK-UP LIGHT ILLUMINATED ALONG WITH MAIN SPOILER FAULT LIGHT. RETURNED FOR LANDING. UPON GEAR DOWN, MAIN SPOILER FAULT LIGHT EXTINGUISHED, LEFT SPOILER GLARESHIELD LIGHTS ILLUMINATED. C/W FAULT ISO CHART 32-09-00, PAGE 138, FIG 110. NO FAULTS FOUND, C/W LIFT SPOILER SYSTEM ANNUNCIATOR CIRCUIT OPS CHECK IAW 27-61-00, PG 503, PARA 2C. CANNOT DUPLICATE, OPS CHECKS GOOD.