Nope. The timer switches the enlarging lamp on for the set interval of time, then switches it off. There should be an override switch on the timer allowing the lamp to stay on for focus and composition. There should also be an outlet on the timer for the safelight. When the enlarging lamp is on, the safelight should be off and vice-versa. But I'm wondering, do both wires have the same plug? Is there no separate power supply for the dichro head?