Installing a switch/outlet combo

[Bailey]

I have a house that was built in the mid 50's. And our wiring is the old school one black and one white with no ground wire. I am replacing a bathroom outlet that was a switch/outlet combo as well. It is a 3 prong GE outlet that only has 3 wires coming into it from the box. 1 black wire in one corner, 1 black wire in the other corner and both the white wires tied together are in the third spot. I'm installing a Leviton T5225 Combo switch/outlet and can't figure out which wires go to which screw. The old one has the push in style wire clamps as opposed to the new one with the screws. New one has 1 brass, 1 silver, 2 black and one green screw. Any help would be appreciated. Thanks!

[HayZee518]

does the switch control a lighting fixture? my guess is that one black wire goes to one black screw, the other black goes to the brass screw, both whites end up on the nickel screw, the green screw is for the equipment ground [or bare conductor] on the side of the switch/combo where the black screws are, there is a breakout tab that jumps between both black screws. This is common between the outlet and switch. the brass is the switch's output. the white is the neutral for the external circuit and outlet.

[Bailey]

Thanks for answering so quickly. Yes the switch does operate a light. The box had 2 diagrams on it but it was very vague. And the 2 black screws were throwing me off. But the tab connecting the 2 makes sense now. Thanks again for your help. Greatly appreciated.