74ls279 SR latch not working
You need a 5V power supply for that device.

You have a couple of options:


get a 5V supply (a USB charger is perfect.)
use a different device, e.g., 74HC279 that will actually run on 3V


Of the two, getting the 5V supply will be easiest. Small, DIP-package logic like the ‘279 is moving into obsolescence.

Like to play with logic? Consider Silego Greenpak, a small flash-based mixed signal array that can handle lots of smal jobs.