ACR LGT REQUIRED EXCESSIVE AILERON TO CTL ROLL TENDENCY AS SPEED INCREASED DURING CLEAN UP AFTER TKOF. FLT CREW REDUCED SPEED LOWERED FLAPS AND RETUREND TO DEP ARPT.

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AFTER TKOF; UPON RAISING FLAPS; ACFT REQUIRED EXCESSIVE LEFT AILERON TO MAINTAIN LEVEL FLT. SURFACE POS INDICATOR (YAW DAMPERS) INDICATED LOWER RUDDER DEFLECTION TO THE RIGHT. I CALLED FOR FLAPS TO BE LOWERED AND THE RUDDER DEFLECTION DECREASED. I RETURNED TO THE ARPT WHERE IT WAS DETERMINED THE LOWER RUDDER YAW DAMPER HAD DEFLECTED INCORRECTLY. THE SURFACE POS INDICATOR SHOWED (IN FLT) WHAT APPEARED TO BE UPPER RUDDER TO THE LEFT AND LOWER RUDDER TO THE RIGHT; SO I WAS UNSURE WHICH RUDDER WAS ACTING IMPROPERLY. I KNEW THAT WHEN THE ACFT WAS IN A DIRTY CONFIGN THAT I COULD CTL THE ACFT IN A FAIRLY NORMAL MANNER; SO I DID NOT THINK THAT IT WAS APPROPRIATE TO TROUBLESHOOT THE PROB. I SLOWED THE ACFT DOWN; LOWERED THE FLAPS AND RETURNED TO THE TKOF ARPT UNEVENTFULLY. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: MAINT SAID THE PROB WAS A TRANSIENT SIGNAL INPUT AND CHANGED THE DAMPER SENSOR. THE PIC THEN ELECTED TO DEACTIVATE THE LOWER YAW DAMPER AND REDISPATCHED APPLYING DAMPER OUT RESTRICTIONS. AFTER 3 FLT SEGMENTS OTHER YAW DAMPER COMPONENTS WERE CHANGED CORRECTING THE PROB. RPTR SAID HE NOTICED A SLIGHT DEFLECTION OF THE RUDDER POS INDICATOR BEFORE THE FIRST TKOF BUT THOUGHT IT WAS DUE TO 2 SHARP LEFT TURNS MADE WHILE POSITIONING THE ACFT FOR TKOF. ALSO THEY WERE TAXIING FAST AND MADE A ROLLING TKOF; SO CTL CHK WAS NOT AS THOROUGH AS USUAL.