What was found
THREE SEPARATE FLOOR EMERGENCY EXIT LIGHTS INOP. THE LIGHTS COME ON WHEN PUSHING THE TEST BUTTON ON THE #4 ELPS. LIGHTS NOT ILLUMINATED WHEN COCKPIT SWITCH IS SET TO ON OR WHEN LIGHTING POWER IS REMOVED USING ECB PAGE & SWITCH IS IN THE ARMED POSITION. THERE IS POSSIBLY AN INTERNAL FAILURE IN ELPS THAT WON'T TRIGGER LIGHTS UNLESS THE TEST BUTTON IS PRESSED, ALSO NOTED THAT THE TEST CYCLE DOES NOT TURN LIGHTS OFF AS IT SHOULD. REMOVED #4 ELPS DUE TO IT FAILING TO ILLUMINATE 3 EXIT LIGHTS. INSTALLED NEW CUSTOMER SUPPLIED #4 ELPS. ALLOWED TO CHARGE FOR 90 MINUTES. PERFORMED OPS CHECK. NO FURTHER DEFECTS NOTED AT THIS TIME. REF MM J33-53-13.