Why is my IC giving abnormally small voltage outputs?
Three problems:


The inputs of an 'LS type device are internally pulled high (not a problem really, but an observation)
the 'S-' and 'R-' input pins are active low (the switches won't do anything)
The 'LS output high drive is weak (this is why the LED is dim)


How to fix it... make the S and R switches tie to ground instead of +4.5V. Use the Q- to drive the LED in sink configuration, and add a load resistor (about 330 ohms is good.)

Like this:







simulate this circuit &ndash; Schematic created using CircuitLab