What was found
FLT 7314 - CHO-IAD DURING TAXI, AIRCRAFT EXPERIENCED SMOKE BEHIND PANEL AT CENTER WINDSHIELD. PAX DEPLANED ON TAXIWAY. MAINTENANCE INSPECTED ALL WIRING BEHIND INSTRUMENT PANEL. PERFORMED AVIONICS CHECKS WITH RADAR SCREEN DISCONNECTED. NO BLACK SMOKE EVIDENT. PULLED C/B FOR WX RADAR AND WX RADAR SCREEN BOX SUSPECTED BAD. SUBMITTER STATES, SUSPECTED ALSO FMS. PULLED C/B FOR FMS. PERFORMED ENGINE RUNS WITH AVIONICS ON. NO EVIDENCE OF SMOKE AT ASSOCIATED WX RADAR OR FMS. FOUND WATER AND GLYCOL BEHIND PANEL TO BE SOURCE OF SMOKE. AIRCRAFT WAS RELEASED AND RETURNED TO SERVICE. (M)