What was found
PASSING FL 10.0 AT DIFF PRESS 4 PSI MAIN CARGO DOOR WARNING LIGHT IN THE COCKPIT AND BY THE DOOR ILLUMINATED DEPRESSURIZED THE CABIN AT 2 1/2 DIFF PRESS WARNING LIGHT GOES OUT. ADJUSTED CARGO DOOR CLOSED SWITCH AND ADJUSTED TENSION ON GANG BAR IAW ROSENBALM AVIATION MM PG 5-3 PRESSURIZED AIRCRAFT TO 6.5 PSI DIFF PRESS NO LIGHTS NOTED DOOR CLOSES AND LATCHES CORRECTLY AT THIS TIME.