A simple method to check your remote buttons individually, whether it is working properly.
Step 1: Needed
2: A phone with camera integrated
Step 2: Done
open your camera from the phone and keep it top to the remote then press the remote button one by one.
if the remote led blinks the button is working. usually this can't be seen using our naked eye.
Note: if the led blinks it shows only the button is working but some times a button may throw a different frequency (a different hexadecimal value) to check the frequency (value) a TSOP can be used with arduino