What was found
LP NR 3022501; DEPARTING DCA AFTER GEAR RETRACTION, ALL 3 RED UNSAFE LIGHTS REMAINED ILLUMINATED, GEAR DOOR LIGHT EXTINGUISHED. ACCOMPLISHED QRH PROCEDURE WITH NO CHANGE IN INDICATIONS. ACP BITE CHECK OF PSEU, CLEANED LANDING GEAR HANDLE SWITCH S1-89 AND THROTTLE GEAR SWITCHES. OPS CHECK GOOD.