Problem with a infrared integrated transistor IS1U621
It looks like you are smoothing the output rather aggressively with that 47 microfarad capacitor. The IS1U621 is a high frequency remote control receiver, designed to receive pulses at a frequency around 38kHz. That capacitor is effectively a short circuit at that frequency.
Try removing it, or better yet, connecting it's negative end to the negative supply rail so that it acts as a smoothing capacitor for the power supply. The circuit does require a capacitor in your original position, but it's value should be 1nF.

Also, the +5V should be connected via a 47 ohm resistor, not directly.

By the way, the chip will ignore any slow signals at low frequency. It does this to avoid interference from fluorescent lights etc. You will need a high frequency source, such as a remote control transmitter to test it.