What was found
ON TAKEOFF APPROX 1000' AGL GOT AN INTERMITTENT FIREBELL AND S/O SAW CARGO SMOKE WARNING LOWER FWD CARGO ON, THEN THE LIGHT WENT OUT. AML REFLECTED A PREVIOUS WRITEUP ON THE SAME SYS. DEEMED TO RETURN AND LAND IMMEDIATELY. REMOVED SMOKE DETECTORS 1,2,3, & 4. CONNECTED NEW SERVICEABLE SMOKE DECTECTORS 1,2,3 AND 4 FOR OPS CHECK. PERFORMED MAINTENANCE PER MM 26-17-011-2. WILL BE DOING OP CHECK SHORTLY. COMPLIED WITH OPERATIONAL CHECK PER AMM 26-17-011-2. OPERATIONAL CHECKS GOOD. HARDWARE REINSTALLED IN ORGINAL HOLES. COMPLETED WIRING CHECKS IAW TSI AND WDM 26-23-01, NO FAULTS NOTED. FINISHED INSTALLATION OF FWD LOWER CARGO SMOKE DETECTORS AND CEU IAW AMM 26-17-011-2-0,2B AND 26-17-012-2-0,2B